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                          On the Natural Faculties

                                  By Galen


                          On the Natural Faculties

                                  By Galen

                       Translated by Arthur John Brock

                              Book One

     1. Since feeling and voluntary motion are peculiar to animals,
     whilst growth and nutrition are common to plants as well, we may
     look on the former as effects of the soul and the latter as
     effects of the nature. And if there be anyone who allows a share
     in soul to plants as well, and separates the two kinds of soul,
     naming the kind in question vegetative, and the other sensory,
     this person is not saying anything else, although his language is
     somewhat unusual. We, however, for our part, are convinced that
     the chief merit of language is clearness, and we know that nothing
     detracts so much from this as do unfamiliar terms; accordingly we
     employ those terms which the bulk of people are accustomed to use,
     and we say that animals are governed at once by their soul and by
     their nature, and plants by their nature alone, and that growth
     and nutrition are the effects of nature, not of soul.

     2. Thus we shall enquire, in the course of this treatise, from
     what faculties these effects themselves, as well as any other
     effects of nature which there may be, take their origin.

     First, however, we must distinguish and explain clearly the
     various terms which we are going to use in this treatise, and to
     what things we apply them; and this will prove to be not merely an
     explanation of terms but at the same time a demonstration of the
     effects of nature.

     When, therefore, such and such a body undergoes no change from its
     existing state, we say that it is at rest; but, not withstanding,
     if it departs from this in any respect we then say that in this
     respect it undergoes motion. Accordingly, when it departs in
     various ways from its preexisting state, it will be said to
     undergo various kinds of motion. Thus, if that which is white
     becomes black, or what is black becomes white, it undergoes motion
     in respect to colour; or if what was previously sweet now becomes
     bitter, or, conversely, from being bitter now becomes sweet, it
     will be said to undergo motion in respect to flavour; to both of
     these instances, as well as to those previously mentioned, we
     shall apply the term qualitative motion. And further, it is not
     only things which are altered in regard to colour and flavour
     which, we say, undergo motion; when a warm thing becomes cold, and
     a cold warm, here too we speak of its undergoing motion; similarly
     also when anything moist becomes dry, or dry moist. Now, the
     common term which we apply to all these cases is alteration.

     This is one kind of motion. But there is another kind which occurs
     in bodies which change their position, or as we say, pass from one
     place to another; the name of this is transference.

     These two kinds of motion, then, are simple and primary, while
     compounded from them we have growth and decay, as when a small
     thing becomes bigger, or a big thing smaller, each retaining at
     the same time its particular form. And two other kinds of motion
     are genesis and destruction, genesis being a coming into
     existence, and destruction being the opposite.

     Now, common to all kinds of motion is change from the preexisting
     state, while common to all conditions of rest is retention of the
     preexisting state. The Sophists, however, while allowing that
     bread in turning into blood becomes changed as regards sight,
     taste, and touch, will not agree that this change occurs in
     reality. Thus some of them hold that all such phenomena are tricks
     and illusions of our senses; the senses, they say, are affected
     now in one way, now in another, whereas the underlying substance
     does not admit of any of these changes to which the names are
     given. Others (such as Anaxagoras) will have it that the qualities
     do exist in it, but that they are unchangeable and immutable from
     eternity to eternity, and that these apparent alterations are
     brought about by separation and combination.

     Now, if I were to go out of my way to confute these people, my
     subsidiary task would be greater than my main one. Thus, if they
     do not know all that has been written, "On Complete Alteration of
     Substance" by Aristotle, and after him by Chrysippus, I must beg
     of them to make themselves familiar with these men's writings. If,
     however, they know these, and yet willingly prefer the worse views
     to the better, they will doubtless consider my arguments foolish
     also. I have shown elsewhere that these opinions were shared by
     Hippocrates, who lived much earlier than Aristotle. In fact, all
     those known to us who have been both physicians and philosophers
     Hippocrates was the first who took in hand to demonstrate that
     there are, in all, four mutually interacting qualities, and that
     to the operation of these is due the genesis and destruction of
     all things that come into and pass out of being. Nay, more;
     Hippocrates was also the first to recognise that all these
     qualities undergo an intimate mingling with one another; and at
     least the beginnings of the proofs to which Aristotle later set
     his hand are to be found first in the writings of Hippocrates.

     As to whether we are to suppose that the substances as well as
     their qualities undergo this intimate mingling, as Zeno of Citium
     afterwards declared, I do not think it necessary to go further
     into this question in the present treatise; for immediate purposes
     we only need to recognize the complete alteration of substance. In
     this way, nobody will suppose that bread represents a kind of
     meeting-place for bone, flesh, nerve, and all the other parts, and
     that each of these subsequently becomes separated in the body and
     goes to join its own kind; before any separation takes place, the
     whole of the bread obviously becomes blood; (at any rate, if a man
     takes no other food for a prolonged period, he will have blood
     enclosed in his veins all the same). And clearly this disproves
     the view of those who consider the elements unchangeable, as also,
     for that matter, does the oil which is entirely used up in the
     flame of the lamp, or the faggots which, in a somewhat longer
     time, turn into fire.

     I said, however, that I was not going to enter into an argument
     with these people, and it was only because the example was drawn
     from the subject-matter of medicine, and because I need it for the
     present treatise, that I have mentioned it. We shall then, as I
     said, renounce our controversy with them, since those who wish may
     get a good grasp of the views of the ancients from our own
     personal investigations into these matters.

     The discussion which follows we shall devote entirely, as we
     originally proposed, to an enquiry into the number and character
     of the faculties of Nature, and what is the effect which each
     naturally produces. Now, of course, I mean by an effect that which
     has already come into existence and has been completed by the
     activity of these faculties- for example, blood, flesh, or nerve.
     And activity is the name I give to the active change or motion,
     and the cause of this I call a faculty. Thus, when food turns into
     blood, the motion of the food is passive, and that of the vein
     active. Similarly, when the limbs have their position their
     position altered, it is the muscle which produces, and the bones
     which undergo the motion. In these cases I call the motion of the
     vein and of the muscle an activity, and that of the food and the
     bones a symptom or affection, since the first group undergoes
     alteration and the second group is merely transported. One might,
     therefore, also speak of the activity as an effect of Nature- for
     example, digestion, absorption, blood-production; one could not,
     however, in every case call the effect an activity; thus flesh is
     an effect of Nature, but it is, of course, not an activity. It is,
     therefore, clear that one of these terms is used in two senses,
     but not the other.

     3. It appears to me, then, that the vein, as well as each of the
     other parts, functions in such and such a way according to the
     manner in which the four qualities are mixed. There are, however,
     a considerable number of not undistinguished men- philosophers and
     physicians- who refer action to the Warm and the Cold, and who
     subordinate to these, as passive, the Dry and the Moist;
     Aristotle, in fact, was the first who attempted to bring back the
     causes of the various special activities to these principles, and
     he was followed later by the Stoic school. These latter, of
     course, could logically make active principles of the Warm and
     Cold, since they refer the change of the elements themselves into
     one another to certain diffusions and condensations. This does not
     hold of Aristotle, however; seeing that he employed the four
     qualities to explain the genesis of the elements, he ought
     properly to have also referred the causes of all the special
     activities to these. How is it that he uses the four qualities in
     his book "On Genesis and Destruction," whilst in his
     "Meteorology," his "Problems," and many other works he uses the
     uses the two only? Of course, if anyone were to maintain that in
     the case of animals and plants the Warm and Cold are more active,
     the Dry and Moist less so, he might perhaps have even Hippocrates
     on his side; but if he were to say that this happens in all cases,
     he would, I imagine, lack support, not merely from Hippocrates,
     but even from Aristotle himself- if, at least, Aristotle chose to
     remember what he himself taught us in his work "On Genesis and
     Destruction," not as a matter of simple statement, but with an
     accompanying demonstration. I have, however, also investigated
     these questions, in so far as they are of value to a physician, in
     my work "On Temperaments."

     4. The so-called blood-making faculty in the veins, then, as well
     as all the other faculties, fall within the category of relative
     concepts; primarily because the faculty is the cause of the
     activity, but also, accidentally, because it is the cause of the
     effect. But, if the cause is relative to something- for it is the
     cause of what results from it, and of nothing else- it is obvious
     that the faculty also falls into the category of the relative; and
     so long as we are ignorant of the true essence of the cause which
     is operating, we call it a faculty. Thus we say that there exists
     in the veins a blood-making faculty, as also a digestive faculty
     in the stomach, a pulsatile faculty in the heart, and in each of
     the other parts a special faculty corresponding to the function or
     activity of that part. If, therefore, we are to investigate
     methodically the number and kinds of faculties, we must begin with
     the effects; for each of these effects comes from a certain
     activity, and each of these again is preceded by a cause.

     5. The effects of Nature, then, while the animal is still being
     formed in the womb, are all the different parts of its body; and
     after it has been born, an effect in which all parts share is the
     progress of each to its full size, and thereafter its maintenance
     of itself as long as possible.

     The activities corresponding to the three effects mentioned are
     necessarily three- one to each- namely, Genesis, Growth, and
     Nutrition. Genesis, however, is not a simple activity of Nature,
     but is compounded of alteration and of shaping. That is to say, in
     order that bone, nerve, veins, and all other [tissues] may come
     into existence, the underlying substance from which the animal
     springs must be altered; and in order that the substance so
     altered may acquire its appropriate shape and position, its
     cavities, outgrowths, attachments, and so forth, it has to undergo
     a shaping or formative process. One would be justified in calling
     this substance which undergoes alteration the material of the
     animal, just as wood is the material of a ship, and wax of an

     Growth is an increase and expansion in length, breadth, and
     thickness of the solid parts of the animal (those which have been
     subjected to the moulding or shaping process). Nutrition is an
     addition to these, without expansion.

     6. Let us speak then, in the first place, of Genesis, which, as we
     have said, results from alteration together with shaping.

     The seed having been cast into the womb or into the earth (for
     there is no difference), then, after a certain definite period, a
     great number of parts become constituted in the substance which is
     being generated; these differ as regards moisture, dryness,
     coldness and warmth, and in all the other qualities which
     naturally derive therefrom. These derivative qualities, you are
     acquainted with, if you have given any sort of scientific
     consideration to the question of genesis and destruction. For,
     first and foremost after the qualities mentioned come the other
     so-called tangible distinctions, and after them those which appeal
     to taste, smell, and sight. Now, tangible distinctions are
     hardness and softness, viscosity, friability, lightness,
     heaviness, density, rarity, smoothness, roughness, thickness and
     thinness; all of these have been duly mentioned by Aristotle. And
     of course you know those which appeal to taste, smell, and sight.
     Therefore, if you wish to know which alterative faculties are
     primary and elementary, they are moisture, dryness, coldness, and
     warmth, and if you wish to know which ones arise from the
     combination of these, they will be found to be in each animal of a
     number corresponding to its sensible elements. The name sensible
     elements is given to all the homogeneous parts of the body, and
     these are to be detected not by any system, but by personal
     observation of dissections.

     Now Nature constructs bone, cartilage, nerve, membrane, ligament,
     vein, and so forth, at the first stage of the animal's genesis,
     employing at this task a faculty which is, in general terms,
     generative and alterative, and, in more detail, warming, chilling,
     drying, or moistening; or such as spring from the blending of
     these, for example, the bone-producing, nerve-producing, and
     cartilage-producing faculties (since for the sake of clearness
     these names must be used as well).

     Now the peculiar flesh of the liver is of this kind as well, also
     that of the spleen, that of the kidneys, that of the lungs, and
     that of the heart; so also the proper substance of the brain,
     stomach, gullet, intestines, and uterus is a sensible element, of
     similar parts all through, simple, and uncompounded. That is to
     say, if you remove from each of the organs mentioned its arteries,
     veins, and nerves, the substance remaining in each organ is, from
     the point of view of the senses, simple and elementary. As regards
     those organs consisting of two dissimilar coats, of which each is
     simple, of these organs the coats are the are the elements- for
     example, the coats of the stomach, oesophagus, intestines, and
     arteries; each of these two coats has an alterative faculty
     peculiar to it, which has engendered it from the menstrual blood
     of the mother. Thus the special alterative faculties in each
     animal are of the same number as the elementary parts; and
     further, the activities must necessarily correspond each to one of
     the special parts, just as each part has its special use- for
     example, those ducts which extend from the kidneys into the
     bladder, and which are called ureters; for these are not arteries,
     since they do not pulsate nor do they consist of two coats; and
     they are not veins, since they neither contain blood, nor do their
     coats in any way resemble those of veins; from nerves they differ
     still more than from the structures mentioned.

     "What, then, are they?" someone asks- as though every part must
     necessarily be either an artery, a vein, a nerve, or a complex of
     these, and as though the truth were not what I am now stating,
     namely, that every one of the various organs has its own
     particular substance. For in fact the two bladders- that which
     receives the urine, and that which receives the yellow bile- not
     only differ from all other organs, but also from one another.
     Further, the ducts which spring out like kinds of conduits from
     the gall-bladder and which pass into the liver have no resemblance
     either to arteries, veins or nerves. But these parts have been
     treated at a greater length in my work "On the Anatomy of
     Hippocrates," as well as elsewhere.

     As for the actual substance of the coats of the stomach,
     intestine, and uterus, each of these has been rendered what it is
     by a special alterative faculty of Nature; while the bringing of
     these together, the therewith of the structures which are inserted
     into them, the outgrowth into the intestine, the shape of the
     inner cavities, and the like, have all been determined by a
     faculty which we call the shaping or formative faculty; this
     faculty we also state to be artistic- nay, the best and highest
     art- doing everything for some purpose, so that there is nothing
     ineffective or superfluous, or capable of being better disposed.
     This, however, I shall demonstrate in my work "On the Use of

     7. Passing now to the faculty of Growth let us first mention that
     this, too, is present in the foetus in utero as is also the
     nutritive faculty, but that at that stage these two faculties are,
     as it were, handmaids to those already mentioned, and do not
     possess in themselves supreme authority. When, however, the animal
     has attained its complete size, then, during the whole period
     following its birth and until the acme is reached, the faculty of
     growth is predominant, while the alterative and nutritive
     faculties are accessory- in fact, act as its handmaids. What,
     then, is the property of this faculty of growth? To extend in
     every direction that which has already come into existence- that
     is to say, the solid parts of the body, the arteries, veins,
     nerves, bones, cartilages, membranes, ligaments, and the various
     coats which we have just called elementary, homogeneous, and
     simple. And I shall state in what way they gain this extension in
     every direction, first giving an illustration for the sake of

     Children take the bladders of pigs, fill them with air, and then
     rub them on ashes near the fire, so as to warm, but not to injure
     them. This is a common game in the district of Ionia, and among
     not a few other nations. As they rub, they sing songs, to a
     certain measure, time, and rhythm, and all their words are an
     exhortation to the bladder to increase in size. When it appears to
     them fairly well distended, they again blow air into it and expand
     it further; then they rub it again. This they do several times,
     until the bladder seems to them to have become large enough. Now,
     clearly, in these doings of the children, the more the interior
     cavity of the bladder increases in size, the thinner, necessarily,
     does its substance become. But, if the children were able to bring
     nourishment to this thin part, then they would make the bladder
     big in the same way that Nature does. As it is, however, they
     cannot do what Nature does, for to imitate this is beyond the
     power not only of children, but of any one soever; it is a
     property of Nature alone.

     It will now, therefore, be clear to you that nutrition is a
     necessity for growing things. For if such bodies were distended,
     but not at the same time nourished, they would take on a false
     appearance of growth, not a true growth. And further, to be
     distended in all directions belongs only to bodies whose growth is
     directed by Nature; for those which are distended by us undergo
     this distension in one direction but grow less in the others; it
     is impossible to find a body which will remain entire and not be
     torn through whilst we stretch it in the three dimensions. Thus
     Nature alone has the power to expand a body in all directions so
     that it remains unruptured and preserves completely its previous

     Such then is growth, and it cannot occur without the nutriment
     which flows to the part and is worked up into it.

     8. We have, then, it seems, arrived at the subject of Nutrition,
     which is the third and remaining consideration which we proposed
     at the outset. For, when the matter which flows to each part of
     the body in the form of nutriment is being worked up into it, this
     activity is nutrition, and its cause is the nutritive faculty. Of
     course, the kind of activity here involved is also an alteration,
     but not an alteration like that occurring at the stage of genesis.
     For in the latter case something comes into existence which did
     not exist previously, while in nutrition the inflowing material
     becomes assimilated to that which has already come into existence.
     Therefore, the former kind of alteration has with reason been
     termed genesis, and the latter, assimilation.

     9. Now, since the three faculties of Nature have been exhaustively
     dealt with, and the animal would appear not to need any others
     (being possessed of the means for growing, for attaining
     completion, and for maintaining itself as long a time as
     possible), this treatise might seem to be already complete, and to
     constitute an exposition of all the faculties of Nature. If,
     however, one considers that it has not yet touched upon any of the
     parts of the animal (I mean the stomach, intestines, liver, and
     the like), and that it has not dealt with the faculties resident
     in these, it will seem as though merely a kind of introduction had
     been given to the practical parts of our teaching. For the whole
     matter is as follows: Genesis, growth, and nutrition are the
     first, and, so to say, the principal effects of Nature; similarly
     also the faculties which produce these effects- the first
     faculties- are three in number, and are the most dominating of
     all. But as has already been shown, these need the service both of
     each other, and of yet different faculties. Now, these which the
     faculties of generation and growth require have been stated. I
     shall now say what ones the nutritive faculty requires.

     10. For I believe that I shall prove that the organs which have to
     do with the disposal of the nutriment, as also their faculties,
     exist for the sake of this nutritive faculty. For since the action
     of this faculty is assimilation, and it is impossible for anything
     to be assimilated by, and to change into anything else unless they
     already possess a certain community and affinity in their
     qualities, therefore, in the first place, any animal cannot
     naturally derive nourishment from any kind of food, and secondly,
     even in the case of those from which it can do so, it cannot do
     this at once. Therefore, by reason of this law, every animal needs
     several organs for altering the nutriment. For in order that the
     yellow may become red, and the red yellow, one simple process of
     alteration is required, but in order that the white may become
     black, and the black white, all the intermediate stages are
     needed. So also, a thing which is very soft cannot all at once
     become very hard, nor vice versa; nor, similarly can anything
     which has a very bad smell suddenly become quite fragrant, nor
     again, can the converse happen.

     How, then, could blood ever turn into bone, without having first
     become, as far as possible, thickened and white? And how could
     bread turn into blood without having gradually parted with its
     whiteness and gradually acquired redness? Thus it is quite easy
     for blood to become flesh; for, if Nature thicken it to such an
     extent that it acquires a certain consistency and ceases to be
     fluid, it thus becomes original newly-formed flesh; but in order
     that blood may turn into bone, much time is needed and much
     elaboration and transformation of the blood. Further, it is quite
     clear that bread, and, more particularly lettuce, beet, and the
     like, require a great deal of alteration, in order to become

     This, then, is one reason why there are so many organs concerned
     in the alteration of food. A second reason is the nature of the
     superfluities. For, as we are unable to draw any nourishment from
     grass, although this is possible for cattle, similarly we can
     derive nourishment from radishes, albeit not to the same extent as
     from meat; for almost the whole of the latter is mastered by our
     natures; it is transformed and altered and constituted useful
     blood; but, not withstanding, in the radish, what is appropriate
     and capable of being altered (and that only with difficulty, and
     with much labour) is the very smallest part; almost the whole of
     it is surplus matter, and passes through the digestive organs,
     only a very little being taken up into the veins as blood- nor is
     this itself entirely utilisable blood. Nature, therefore, had need
     of a second process of separation for the superfluities in the
     veins. Moreover, these superfluities need, on the one hand,
     certain fresh routes to conduct them to the outlets, so that they
     may not spoil the useful substances, and they also need certain
     reservoirs, as it were, in which they are collected till they
     reach a sufficient quantity, and are then discharged.

     Thus, then, you have discovered bodily parts of a second kind,
     consecrated in this case to the [removal of the] superfluities of
     the food. There is, however, also a third kind, for carrying the
     pabulum in every direction; these are like a number of roads
     intersecting the whole body.

     Thus there is one entrance- that through the mouth- for all the
     various articles of food. What receives nourishment, however, is
     not one single part, but a great many parts, and these widely
     separated; do not be surprised, therefore, at the abundance of
     organs which Nature has created for the purpose of nutrition. For
     those of them which have to do with alteration prepare the
     nutriment suitable for each part; others separate out the
     superfluities; some pass these along, others store them up, others
     excrete them; some, again, are paths for the transit in all
     directions of the utilisable juices. So, if you wish to gain a
     thorough acquaintance with all the faculties of Nature, you will
     have consider each one of these organs.

     Now in giving an account of these we must begin with those effects
     of Nature, together with their corresponding parts and faculties,
     which are closely connected with the purpose to be achieved.

     11. Let us once more, then, recall the actual purpose for which
     Nature has constructed all these parts. Its name, as previously
     stated, is nutrition, and the definition corresponding to the name
     is: an assimilation of that which nourishes to that which receives
     nourishment. And in order that this may come about, we must assume
     a preliminary process of adhesion, and for that, again, one of
     presentation. For whenever the juice which is destined to nourish
     any of the parts of the animal is emitted from the vessels, it is
     in the first place dispersed all through this part, next it is
     presented, and next it adheres, and becomes completely

     The so-called white [leprosy] shows the difference between
     assimilation and adhesion, in the same way that the kind of dropsy
     which some people call anasarca clearly distinguishes presentation
     from adhesion. For, of course, the genesis of such a dropsy does
     not come about as do some of the conditions of atrophy and
     wasting, from an insufficient supply of moisture; the flesh is
     obviously moist enough,- in fact it is thoroughly saturated,- and
     each of the solid parts of the body is in a similar condition.
     While, however, the nutriment conveyed to the part does undergo
     presentation, it is still too watery, and is not properly
     transformed into a juice, nor has it acquired that viscous and
     agglutinative quality which results from the operation of innate
     heat; therefore, adhesion cannot come about, since, owing to this
     abundance of thin, crude liquid, the pabulum runs off and easily
     slips away from the solid parts of the body. In white [leprosy],
     again, there is adhesion of the nutriment but no real
     assimilation. From this it is clear that what I have just said is
     correct, namely, that in that part which is to be nourished there
     must first occur presentation, next adhesion, and finally
     assimilation proper.

     Strictly speaking, then, nutriment is that which is actually
     nourishing, while the quasi-nutriment which is not yet nourishing
     (e.g. matter which is undergoing adhesion or presentation) is not,
     strictly speaking, nutriment, but is so called only by an
     equivocation. Also, that which is still contained in the veins,
     and still more, that which is in the stomach, from the fact that
     it is destined to nourish if properly elaborated, has been called
     "nutriment." Similarly we call the various kinds of food
     "nutriment," not because they are already nourishing the animal,
     nor because they exist in the same state as the material which
     actually is nourishing it, but because they are able and destined
     to nourish it if they be properly elaborated.

     This was also what Hippocrates said, viz., "Nutriment is what is
     engaged in nourishing, as also is quasi-nutriment, and what is
     destined to be nutriment." For to that which is already being
     assimilated he gave the name of nutriment; to the similar material
     which is being presented or becoming adherent, the name of
     quasi-nutriment; and to everything else- that is, contained in the
     stomach and veins- the name of destined nutriment.

     12. It is quite clear, therefore, that nutrition must necessarily
     be a process of assimilation of that which is nourishing to that
     which is being nourished. Some, however, say that this
     assimilation does not occur in reality, but is merely apparent;
     these are the people who think that Nature is not artistic, that
     she does not show forethought for the animal's welfare, and that
     she has absolutely no native powers whereby she alters some
     substances, attracts others, and discharges others.

     Now, speaking generally, there have arisen the following two sects
     in medicine and philosophy among those who have made any definite
     pronouncement regarding Nature. I speak, of course, of such of
     them as know what they are talking about, and who realize the
     logical sequence of their hypotheses, and stand by them; as for
     those who cannot understand even this, but who simply talk any
     nonsense that comes to their tongues, and who do not remain
     definitely attached either to one sect or the other- such people
     are not even worth mentioning.

     What, then, are these sects, and what are the logical consequences
     of their hypotheses? The one class supposes that all substance
     which is subject to genesis and destruction is at once continuous
     and susceptible of alteration. The other school assumes substance
     to be unchangeable, unalterable, and subdivided into fine
     particles, which are separated from one another by empty spaces.

     All people, therefore, who can appreciate the logical sequence of
     an hypothesis hold that, according to the second teaching, there
     does not exist any substance or faculty peculiar either to Nature
     or to Soul, but that these result from the way in which the
     primary corpuscles, which are unaffected by change, come together.
     According to the first-mentioned teaching, on the other hand,
     Nature is not posterior to the corpuscles, but is a long way prior
     to them and older than they; and therefore in their view it is
     Nature which puts together the bodies both of plants and animals;
     and this she does by virtue of certain faculties which she
     possesses- these being, on the one hand, attractive and
     assimilative of what is appropriate, and, on the other, of what is
     foreign. Further, she skilfully moulds everything during the stage
     of genesis; and she also provides for the creatures after birth,
     employing here other faculties again, namely, one of affection and
     forethought for offspring, and one of sociability and friendship
     for kindred. According to the other school, none of these things
     exist in the natures [of living things], nor is there in the soul
     any original innate idea, whether of agreement or difference, of
     separation or synthesis, of justice or injustice, of the beautiful
     or ugly; all such things, they say, arise in us from sensation and
     through sensation, and animals are steered by certain images and

     Some of these people have even expressly declared that the soul
     possesses no reasoning faculty, but that we are led like cattle by
     the impression of our senses, and are unable to refuse or dissent
     from anything. In their view, obviously, courage, wisdom,
     temperance, and self-control are all mere nonsense, we do not love
     either each other or our offspring, nor do the gods care anything
     for us. This school also despises dreams, birds, omens, and the
     whole of astrology, subjects with which we have dealt at greater
     length in another work, in which we discuss the views of
     Asclepiades the physician. Those who wish to do so may familiarize
     themselves with these arguments, and they may also consider at
     this point which of the two roads lying before us is the better
     one to take. Hippocrates took the first-mentioned. According to
     this teaching, substance is one and is subject to alteration;
     there is a consensus in the movements of air and fluid throughout
     the whole body; Nature acts throughout in an artistic and
     equitable manner, having certain faculties, by virtue of which
     each part of the body draws to itself the juice which is proper to
     it, and, having done so, attaches it to every portion of itself,
     and completely assimilates it; while such part of the juice as has
     not been mastered, and is not capable of undergoing complete
     alteration and being assimilated to the part which is being
     nourished, is got rid of by yet another (an expulsive) faculty.

     13. Now the extent of exactitude and truth in the doctrines of
     Hippocrates may be gauged, not merely from the way in which his
     opponents are at variance with obvious facts, but also from the
     various subjects of natural research themselves- the functions of
     animals, and the rest. For those people who do not believe that
     there exists in any part of the animal a faculty for attracting
     its own special quality are compelled repeatedly to deny obvious
     facts. For instance, Asclepiades, the physician, did this in the
     case of the kidneys. That these are organs for secreting
     [separating out] the urine, was the belief not only of
     Hippocrates, Diocles, Erasistratus, Praxagoras, and all other
     physicians of eminence, but practically every butcher is aware of
     this, from the fact that he daily observes both the position of
     the kidneys and the duct (termed the ureter) which runs from each
     kidney into the bladder, and from this arrangement he infers their
     characteristic use and faculty. But, even leaving the butchers
     aside, all people who suffer either from frequent dysuria or from
     retention of urine call themselves "nephritics," when they feel
     pain in the loins and pass sandy matter in their water.

     I do not suppose that Asclepiades ever saw a stone which had been
     passed by one of these sufferers, or observed that this was
     preceded by a sharp pain in the region between kidneys and bladder
     as the stone traversed the ureter, or that, when the stone was
     passed, both the pain and the retention at once ceased. It is
     worth while, then, learning how his theory accounts for the
     presence of urine in the bladder, and one is forced to marvel at
     the ingenuity of a man who puts aside these broad, clearly visible
     routes, and postulates others which are narrow, invisible- indeed,
     entirely imperceptible. His view, in fact, is that the fluid which
     we drink passes into the bladder by being resolved into vapours,
     and that, when these have been again condensed, it thus regains
     its previous form, and turns from vapour into fluid. He simply
     looks upon the bladder as a sponge or a piece of wool, and not as
     the perfectly compact and impervious body that it is, with two
     very strong coats. For if we say that the vapours pass through
     these coats, why should they not pass through the peritoneum and
     the diaphragm, thus filling the whole abdominal cavity and thorax
     with water? "But," says he, "of course the peritoneal coat is more
     impervious than the bladder, and this is why it keeps out the
     vapours, while the bladder admits them." Yet if he had ever
     practised anatomy, he might have known that the outer coat of the
     bladder springs from the peritoneum and is essentially the same as
     it, and that the inner coat, which is peculiar to the bladder, is
     more than twice as thick as the former.

     Perhaps, however, it is not the thickness or thinness of the
     coats, but the situation of the bladder, which is the reason for
     the vapours being carried into it? On the contrary, even if it
     were probable for every other reason that the vapours accumulate
     there, yet the situation of the bladder would be enough in itself
     to prevent this. For the bladder is situated below, whereas
     vapours have a natural tendency to rise upwards; thus they would
     fill all the region of the thorax and lungs long before they came
     to the bladder.

     But why do I mention the situation of the bladder, peritoneum, and
     thorax? For surely, when the vapours have passed through the coats
     of the stomach and intestines, it is in the space between these
     and the peritoneum that they will collect and become liquefied
     (just as in dropsical subjects it is in this region that most of
     the water gathers). Otherwise the vapours must necessarily pass
     straight forward through everything which in any way comes in
     contact with them, and will never come to a standstill. But, if
     this be assumed, then they will traverse not merely the peritoneum
     but also the epigastrium, and will become dispersed into the
     surrounding air; otherwise they will certainly collect under the

     Even these considerations, however, our present-day Asclepiadeans
     attempt to answer, despite the fact that they always get soundly
     laughed at by all who happen to be present at their disputations
     on these subjects- so difficult an evil to get rid of is this
     sectarian partizanship, so excessively resistant to all cleansing
     processes, harder to heal than any itch!

     Thus, one of our Sophists who is a thoroughly hardened disputer
     and as skilful a master of language as there ever was, once got
     into a discussion with me on this subject; so far from being put
     out of countenance by any of the above-mentioned considerations,
     he even expressed his surprise that I should try to overturn
     obvious facts by ridiculous arguments! "For," said he, "one may
     clearly observe any day in the case of any bladder, that, if one
     fills it with water or air and then ties up its neck and squeezes
     it all round, it does not let anything out at any point, but
     accurately retains all its contents. And surely," said he, "if
     there were any large and perceptible channels coming into it from
     the kidneys the liquid would run out through these when the
     bladder was squeezed, in the same way that it entered?" Having
     abruptly made these and similar remarks in precise and clear
     tones, he concluded by jumping up and departing- leaving me as
     though I were quite incapable of finding any plausible answer!

     The fact is that those who are enslaved to their sects are not
     merely devoid of all sound knowledge, but they will not even stop
     to learn! Instead of listening, as they ought, to the reason why
     liquid can enter the bladder through the ureters, but is unable to
     go back again the same way,- instead of admiring Nature's artistic
     skill- they refuse to learn; they even go so far as to scoff, and
     maintain that the kidneys, as well as many other things, have been
     made by Nature for no purpose! And some of them who had allowed
     themselves to be shown the ureters coming from the kidneys and
     becoming implanted in the bladder, even had the audacity to say
     that these also existed for no purpose; and others said that they
     were spermatic ducts, and that this was why they were inserted
     into the neck of the bladder and not into its cavity. When,
     therefore, we had demonstrated to them the real spermatic ducts
     entering the neck of the bladder lower down than the ureters, we
     supposed that, if we had not done so before, we would now at least
     draw them away from their false assumptions, and convert them
     forthwith to the opposite view. But even this they presumed to
     dispute, and said that it was not to be wondered at that the semen
     should remain longer in these latter ducts, these being more
     constricted, and that it should flow quickly down the ducts which
     came from the kidneys, seeing that these were well dilated. We
     were, therefore, further compelled to show them in a still living
     animal, the urine plainly running out through the ureters into the
     bladder; even thus we hardly hoped to check their nonsensical

     Now the method of demonstration is as follows. One has to divide
     the peritoneum in front of the ureters, then secure these with
     ligatures, and next, having bandaged up the animal, let him go
     (for he will not continue to urinate). After this one loosens the
     external bandages and shows the bladder empty and the ureters
     quite full and distended- in fact almost on the point of
     rupturing; on removing the ligature from them, one then plainly
     sees the bladder becoming filled with urine.

     When this has been made quite clear, then, before the animal
     urinates, one has to tie a ligature round his penis and then to
     squeeze the bladder all over; still nothing goes back through the
     ureters to the kidneys. Here, then, it becomes obvious that not
     only in a dead animal, but in one which is still living, the
     ureters are prevented from receiving back the urine from the
     bladder. These observations having been made, one now loosens the
     ligature from the animal's penis and allows him to urinate, then
     again ligatures one of the ureters and leaves the other to
     discharge into the bladder. Allowing, then, some time to elapse,
     one now demonstrates that the ureter which was ligatured is
     obviously full and distended on the side next to the kidneys,
     while the other one- that from which the ligature had been taken-
     is itself flaccid, but has filled the bladder with urine. Then,
     again, one must divide the full ureter, and demonstrate how the
     urine spurts out of it, like blood in the operation of
     vene-section; and after this one cuts through the other also, and
     both being thus divided, one bandages up the animal externally.
     Then when enough time seems to have elapsed, one takes off the
     bandages; the bladder will now be found empty, and the whole
     region between the intestines and the peritoneum full of urine, as
     if the animal were suffering from dropsy. Now, if anyone will but
     test this for himself on an animal, I think he will strongly
     condemn the rashness of Asclepiades, and if he also learns the
     reason why nothing regurgitates from the bladder into the ureters,
     I think he will be persuaded by this also of the forethought and
     art shown by Nature in relation to animals.

     Now Hippocrates, who was the first known to us of all those who
     have been both physicians and philosophers in as much as he was
     the first to recognize what Nature effects, expresses his
     admiration of her, and is constantly singing her praises and
     calling her "just." Alone, he says, she suffices for the animal in
     every respect, performing of her own accord and without any
     teaching all that is required. Being such, she has, as he
     supposes, certain faculties, one attractive of what is
     appropriate, and another eliminative of what is foreign, and she
     nourishes the animal, makes it grow, and expels its diseases by
     crisis. Therefore he says that there is in our bodies a
     concordance in the movements of air and fluid, and that everything
     is in sympathy. According to Asclepiades, however, nothing is
     naturally in sympathy with anything else, all substance being
     divided and broken up into inharmonious elements and absurd
     "molecules." Necessarily, then, besides making countless other
     statements in opposition to plain fact, he was ignorant of
     Nature's faculties, both that attracting what is appropriate, and
     that expelling what is foreign. Thus he invented some wretched
     nonsense to explain blood-production and anadosis, and, being
     utterly unable to find anything to say regarding the clearing-out
     of superfluities, he did not hesitate to join issue with obvious
     facts, and, in this matter of urinary secretion, to deprive both
     the kidneys and the ureters of their activity, by assuming that
     there were certain invisible channels opening into the bladder. It
     was, of course, a grand and impressive thing to do, to mistrust
     the obvious, and to pin one's faith in things which could not be

     Also, in the matter of the yellow bile, he makes an even grander
     and more spirited venture; for he says this is actually generated
     in the bile-ducts, not merely separated out.

     How comes it, then, that in cases of jaundice two things happen at
     the same time- that the dejections contain absolutely no bile, and
     that the whole body becomes full of it? He is forced here again to
     talk nonsense, just as he did in regard to the urine. He also
     talks no less nonsense about the black bile and the spleen, not
     understanding what was said by Hippocrates; and he attempts in
     stupid- I might say insane- language, to contradict what he knows
     nothing about.

     And what profit did he derive from these opinions from the point
     of view of treatment? He neither was able to cure a kidney
     ailment, nor jaundice, nor a disease of black bile, nor would he
     agree with the view held not merely by Hippocrates but by all men
     regarding drugs- that some of them purge away yellow bile, and
     others black, some again phlegm, and others the thin and watery
     superfluity; he held that all the substances evacuated were
     produced by the drugs themselves, just as yellow bile is produced
     by the biliary passages! It matters nothing, according to this
     extraordinary man, whether we give a hydragogue or a cholagogue in
     a case of dropsy, for these all equally purge and dissolve the
     body, and produce a solution having such and such an appearance,
     which did not exist as such before!

     Must we not, therefore, suppose he was either mad, or entirely
     unacquainted with practical medicine? For who does not know that
     if a drug for attracting phlegm be given in a case of jaundice it
     will not even evacuate four cyathi of phlegm? Similarly also if
     one of the hydragogues be given. A cholagogue, on the other hand,
     clears away a great quantity of bile, and the skin of patients so
     treated at once becomes clear. I myself have, in many cases, after
     treating the liver condition, then removed the disease by means of
     a single purgation; whereas, if one had employed a drug for
     removing phlegm one would have done no good.

     Nor is Hippocrates the only one who knows this to be so, whilst
     those who take experience alone as their starting-point know
     otherwise; they, as well as all physicians who are engaged in the
     practice of medicine, are of this opinion. Asclepiades, however,
     is an exception; he would hold it a betrayal of his assumed
     "elements" to confess the truth about such matters. For if a
     single drug were to be discovered which attracted such and such a
     humour only, there would obviously be danger of the opinion
     gaining ground that there is in every body a faculty which
     attracts its own particular quality. He therefore says that
     safflower, the Cnidian berry, and Hippophaes, do not draw phlegm
     from the body, but actually make it. Moreover, he holds that the
     flower and scales of bronze, and burnt bronze itself, and
     germander, and wild mastich dissolve the body into water, and that
     dropsical patients derive benefit from these substances, not
     because they are purged by them, but because they are rid of
     substances which actually help to increase the disease; for, if
     the medicine does not evacuate the dropsical fluid contained in
     the body, but generates it, it aggravates the condition further.
     Moreover, scammony, according to the Asclepiadean argument, not
     only fails to evacuate the bile from the bodies of jaundiced
     subjects, but actually turns the useful blood into bile, and
     dissolves the body; in fact it does all manner of evil and
     increases the disease.

     And yet this drug may be clearly seen to do good to numbers of
     people! "Yes," says he, "they derive benefit certainly, but merely
     in proportion to the evacuation."... But if you give these cases a
     drug which draws off phlegm they will not be benefited. This is so
     obvious that even those who make experience alone their
     starting-point are aware of it; and these people make it a
     cardinal point of their teaching to trust to no arguments, but
     only to what can be clearly seen. In this, then, they show good
     sense; whereas Asclepiades goes far astray in bidding us distrust
     our senses where obvious facts plainly overturn his hypotheses.
     Much better would it have been for him not to assail obvious
     facts, but rather to devote himself entirely to these.

     Is it, then, these facts only which are plainly irreconcilable
     with the views of Asclepiades? Is not also the fact that in summer
     yellow bile is evacuated in greater quantity by the same drugs,
     and in winter phlegm, and that in a young man more bile is
     evacuated, and in an old man more phlegm? Obviously each drug
     attracts something which already exists, and does not generate
     something previously non-existent. Thus if you give in the summer
     season a drug which attracts phlegm to a young man of a lean and
     warm habit, who has lived neither idly nor too luxuriously, you
     will with great difficulty evacuate a very small quantity of this
     humour, and you will do the man the utmost harm. On the other
     hand, if you give him a cholagogue, you will produce an abundant
     evacuation and not injure him at all.

     Do we still, then, disbelieve that each drug attracts that humour
     which is proper to it? Possibly the adherents of Asclepiades will
     assent to this- or rather, they will- not possibly, but certainly-
     declare that they disbelieve it, lest they should betray their
     darling prejudices.

     14. Let us pass on, then, again to another piece of nonsense; for
     the sophists do not allow one to engage in enquiries that are of
     any worth, albeit there are many such; they compel one to spend
     one's time in dissipating the fallacious arguments which they
     bring forward.

     What, then, is this piece of nonsense? It has to do with the
     famous and far-renowned stone which draws iron [the lodestone]. It
     might be thought that this would draw their minds to a belief that
     there are in all bodies certain faculties by which they attract
     their own proper qualities.

     Now Epicurus, despite the fact that he employs in his "Physics"
     elements similar to those of Asclepiades, yet allows that iron is
     attracted by the lodestone, and chaff by amber. He even tries to
     give the cause of the phenomenon. His view is that the atoms which
     flow from the stone are related in shape to those flowing from the
     iron, and so they become easily interlocked with one another; thus
     it is that, after colliding with each of the two compact masses
     (the stone and the iron) they then rebound into the middle and so
     become entangled with each other, and draw the iron after them. So
     far, then, as his hypotheses regarding causation go, he is
     perfectly unconvincing; nevertheless, he does grant that there is
     an attraction. Further, he says that it is on similar principles
     that there occur in the bodies of animals the dispersal of
     nutriment and the discharge of waste matters, as also the actions
     of cathartic drugs.

     Asclepiades, however, who viewed with suspicion the incredible
     character of the cause mentioned, and who saw no other credible
     cause on the basis of his supposed elements, shamelessly had
     recourse to the statement that nothing is in any way attracted by
     anything else. Now, if he was dissatisfied with what Epicurus
     said, and had nothing better to say himself, he ought to have
     refrained from making hypotheses, and should have said that Nature
     is a constructive artist and that the substance of things is
     always tending towards unity and also towards alteration because
     its own parts act upon and are acted upon by one another. For, if
     he had assumed this, it would not have been difficult to allow
     that this constructive Nature has powers which attract appropriate
     and expel alien matter. For in no other way could she be
     constructive, preservative of the animal, and eliminative of its
     diseases, unless it be allowed that she conserves what is
     appropriate and discharges what is foreign.

     But in this matter, too, Asclepiades realized the logical sequence
     of the principles he had assumed; he showed no scruples, however,
     in opposing plain fact; he joins issue in this matter also, not
     merely with all physicians, but with everyone else, and maintains
     that there is no such thing as a crisis, or critical day, and that
     Nature does absolutely nothing for the preservation of the animal.
     For his constant aim is to follow out logical consequences and to
     upset obvious fact, in this respect being opposed to Epicurus; for
     the latter always stated the observed fact, although he gives an
     ineffective explanation of it. For, that these small corpuscles
     belonging to the lodestone rebound, and become entangled with
     other similar particles of the iron, and that then, by means of
     this entanglement (which cannot be seen anywhere) such a heavy
     substance as iron is attracted- I fail to understand how anybody
     could believe this. Even if we admit this, the same principle will
     not explain the fact that, when the iron has another piece brought
     in contact with it, this becomes attached to it.

     For what are we to say? That, forsooth, some of the particles that
     flow from the lodestone collide with the iron and then rebound
     back, and that it is by these that the iron becomes suspended?
     that others penetrate into it, and rapidly pass through it by way
     of its empty channels? that these then collide with the second
     piece of iron and are not able to penetrate it although they
     penetrated the first piece? and that they then course back to the
     first piece, and produce entanglements like the former ones?

     The hypothesis here becomes clearly refuted by its absurdity. As a
     matter of fact, I have seen five writing-stylets of iron attached
     to one another in a line, only the first one being in contact with
     the lodestone, and the power being transmitted through it to the
     others. Moreover, it cannot be said that if you bring a second
     stylet into contact with the lower end of the first, it becomes
     held, attached, and suspended, whereas, if you apply it to any
     other part of the side it does not become attached. For the power
     of the lodestone is distributed in all directions; it merely needs
     to be in contact with the first stylet at any point; from this
     stylet again the power flows, as quick as a thought, all through
     the second, and from that again to the third. Now, if you imagine
     a small lodestone hanging in a house, and in contact with it all
     round a large number of pieces of iron, from them again others,
     from these others, and so on,- all these pieces of iron must
     surely become filled with the corpuscles which emanate from the
     stone; therefore, this first little stone is likely to become
     dissipated by disintegrating into these emanations. Further, even
     if there be no iron in contact with it, it still disperses into
     the air, particularly if this be also warm.

     "Yes," says Epicurus, "but these corpuscles must be looked on as
     exceedingly small, so that some of them are a ten-thousandth part
     of the size of the very smallest particles carried in the air."
     Then do you venture to say that so great a weight of iron can be
     suspended by such small bodies? If each of them is a
     ten-thousandth part as large as the dust particles which are borne
     in the atmosphere, how big must we suppose the hook-like
     extremities by which they interlock with each other to be? For of
     course this is quite the smallest portion of the whole particle.

     Then, again, when a small body becomes entangled with another
     small body, or when a body in motion becomes entangled with
     another also in motion, they do not rebound at once. For, further,
     there will of course be others which break in upon them from
     above, from below, from front and rear, from right and left, and
     which shake and agitate them and never let them rest. Moreover, we
     must perforce suppose that each of these small bodies has a large
     number of these hook-like extremities. For by one it attaches
     itself to its neighbours, by another- the topmost one- to the
     lodestone, and by the bottom one to the iron. For if it were
     attached to the stone above and not interlocked with the iron
     below, this would be of no use. Thus, the upper part of the
     superior extremity must hang from the lodestone, and the iron must
     be attached to the lower end of the inferior extremity; and, since
     they interlock with each other by their sides as well, they must,
     of course, have hooks there too. Keep in mind also, above
     everything, what small bodies these are which possess all these
     different kinds of outgrowths. Still more, remember how, in order
     that the second piece of iron may become attached to the first,
     the third to the second, and to that the fourth, these absurd
     little particles must both penetrate the passages in the first
     piece of iron and at the same time rebound from the piece coming
     next in the series, although this second piece is naturally in
     every way similar to the first.

     Such an hypothesis, once again, is certainly not lacking in
     audacity; in fact, to tell the truth, it is far more shameless
     than the previous ones; according to it, when five similar pieces
     of iron are arranged in a line, the particles of the lodestone
     which easily traverse the first piece of iron rebound from the
     second, and do not pass readily through it in the same way.
     Indeed, it is nonsense, whichever alternative is adopted. For, if
     they do rebound, how then do they pass through into the third
     piece? And if they do not rebound, how does the second piece
     become suspended to the first? For Epicurus himself looked on the
     rebound as the active agent in attraction.

     But, as I have said, one is driven to talk nonsense whenever one
     gets into discussion with such men. Having, therefore, given a
     concise and summary statement of the matter, I wish to be done
     with it. For if one diligently familiarizes oneself with the
     writings of Asclepiades, one will see clearly their logical
     dependence on his first principles, but also their disagreement
     with observed facts. Thus, Epicurus, in his desire to adhere to
     the facts, cuts an awkward figure by aspiring to show that these
     agree with his principles, whereas Asclepiades safeguards the
     sequence of principles, but pays no attention to the obvious fact.
     Whoever, therefore, wishes to expose the absurdity of their
     hypotheses, must, if the argument be in answer to Asclepiades,
     keep in mind his disagreement with observed fact; or if in answer
     to Epicurus, his discordance with his principles. Almost all the
     other sects depending on similar principles are now entirely
     extinct, while these alone maintain a respectable existence still.
     Yet the tenets of Asclepiades have been unanswerably confuted by
     Menodotus the Empiricist, who draws his attention to their
     opposition to phenomena and to each other; and, again, those of
     Epicurus have been confuted by Asclepiades, who adhered always to
     logical sequence, about which Epicurus evidently cares little.

     Now people of the present day do not begin by getting a clear
     comprehension of these sects, as well as of the better ones,
     thereafter devoting a long time to judging and testing the true
     and false in each of them; despite their ignorance, they style
     themselves, some "physicians" and others "philosophers." No
     wonder, then, that they honour the false equally with the true.
     For everyone becomes like the first teacher that he comes across,
     without waiting to learn anything from anybody else. And there are
     some of them, who, even if they meet with more than one teacher,
     are yet so unintelligent and slow-witted that even by the time
     they have reached old age they are still incapable of
     understanding the steps of an argument.... In the old days such
     people used to be set to menial tasks.... What will be the end of
     it God knows!

     Now, we usually refrain from arguing with people whose principles
     are wrong from the outset. Still, having been compelled by the
     natural course of events to enter into some kind of a discussion
     with them, we must add this further to what was said- that it is
     not only cathartic drugs which naturally attract their special
     qualities, but also those which remove thorns and the points of
     arrows such as sometimes become deeply embedded in the flesh.
     Those drugs also which draw out animal poisons or poisons applied
     to arrows all show the same faculty as does the lodestone. Thus, I
     myself have seen a thorn which was embedded in a young man's foot
     fail to come out when we exerted forcible traction with our
     fingers, and yet come away painlessly and rapidly on the
     application of a medicament. Yet even to this some people will
     object, asserting that when the inflammation is dispersed from the
     part the thorn comes away of itself, without being pulled out by
     anything. But these people seem, in the first place, to be unaware
     that there are certain drugs for drawing out inflammation and
     different ones for drawing out embedded substances; and surely if
     it was on the cessation of an inflammation that the abnormal
     matters were expelled, then all drugs which disperse inflammations
     ought ipso facto; to possess the power of extracting these
     substances as well.

     And secondly, these people seem to be unaware of a still more
     surprising fact, namely, that not merely do certain medicaments
     draw out thorns and others poisons, but that of the latter there
     are some which attract the poison of the viper, others that of the
     sting-ray, and others that of some other animal; we can, in fact,
     plainly observe these poisons deposited on the medicaments. Here,
     then, we must praise Epicurus for the respect he shows towards
     obvious facts, but find fault with his views as to causation. For
     how can it be otherwise than extremely foolish to suppose that a
     thorn which we failed to remove by digital traction could be drawn
     out by these minute particles?

     Have we now, therefore, convinced ourselves that everything which
     exists possesses a faculty by which it attracts its proper
     quality, and that some things do this more, and some less?

     Or shall we also furnish our argument with the illustration
     afforded by corn? For those who refuse to admit that anything is
     attracted by anything else, will, I imagine, be here proved more
     ignorant regarding Nature than the very peasants. When, for my own
     part, I first learned of what happens, I was surprised, and felt
     anxious to see it with my own eyes. Afterwards, when experience
     also had confirmed its truth, I sought long among the various
     sects for an explanation, and, with the exception of that which
     gave the first place to attraction, I could find none which even
     approached plausibility, all the others being ridiculous and
     obviously quite untenable.

     What happens, then, is the following. When our peasants are
     bringing corn from the country into the city in wagons, and wish
     to filch some away without being detected, they fill earthen jars
     with water and stand them among the corn; the corn then draws the
     moisture into itself through the jar and acquires additional bulk
     and weight, but the fact is never detected by the onlookers unless
     someone who knew about the trick before makes a more careful
     inspection. Yet, if you care to set down the same vessel in the
     very hot sun, you will find the daily loss to be very little
     indeed. Thus corn has a greater power than extreme solar heat of
     drawing to itself the moisture in its neighbourhood. Thus the
     theory that the water is carried towards the rarefied part of the
     air surrounding us (particularly when that is distinctly warm) is
     utter nonsense; for although it is much more rarefied there than
     it is amongst the corn, yet it does not take up a tenth part of
     the moisture which the corn does.

     15. Since, then, we have talked sufficient nonsense- not
     willingly, but because we were forced, as the proverb says, "to
     behave madly among madmen"- let us return again to the subject of
     urinary secretion. Here let us forget the absurdities of
     Asclepiades, and, in company with those who are persuaded that the
     urine does pass through the kidneys, let us consider what is the
     character of this function. For, most assuredly, either the urine
     is conveyed by its own motion to the kidneys, considering this the
     better course (as do we when we go off to market!), or, if this be
     impossible, then some other reason for its conveyance must be
     found. What, then, is this? If we are not going to grant the
     kidneys a faculty for attracting this particular quality, as
     Hippocrates held, we shall discover no other reason. For, surely
     everyone sees that either the kidneys must attract the urine, or
     the veins must propel it- if, that is, it does not move of itself.
     But if the veins did exert a propulsive action when they contract,
     they would squeeze out into the kidneys not merely the urine, but
     along with it the whole of the blood which they contain. And if
     this is impossible, as we shall show, the remaining explanation is
     that the kidneys do exert traction.

     And how is propulsion by the veins impossible? The situation of
     the kidneys is against it. They do not occupy a position beneath
     the hollow vein [vena cava] as does the sieve-like [ethmoid]
     passage in the nose and palate in relation to the surplus matter
     from the brain; they are situated on both sides of it. Besides, if
     the kidneys are like sieves, and readily let the thinner serous
     [whey-like] portion through, and keep out the thicker portion,
     then the whole of the blood contained in the vena cava must go to
     them, just as the whole of the wine is thrown into the filters.
     Further, the example of milk being made into cheese will show
     clearly what I mean. For this, too, although it is all thrown into
     the wicker strainers, does not all percolate through; such part of
     it as is too fine in proportion to the width of the meshes passes
     downwards, and this is called whey [serum]; the remaining thick
     portion which is destined to become cheese cannot get down, since
     the pores of the strainers will not admit it. Thus it is that, if
     the blood-serum has similarly to percolate through the kidneys,
     the whole of the blood must come to them, and not merely one part
     of it.

     What, then, is the appearance as found on dissection?
     One division of the vena cava is carried upwards to the heart, and
     the other mounts upon the spine and extends along its whole length
     as far as the legs; thus one division does not even come near the
     kidneys, while the other approaches them but is certainly not
     inserted into them. Now, if the blood were destined to be purified
     by them as if they were sieves, the whole of it would have to fall
     into them, the thin part being and the thick part retained above.
     But, as a matter of fact, this is not so. For the kidneys lie on
     either side of the vena cava. They therefore do not act like
     sieves, filtering fluid sent to them by the vena cava, and
     themselves contributing no force. They obviously exert traction;
     for this is the only remaining alternative.

     How, then, do they exert this traction? If, as Epicurus thinks,
     all attraction takes place by virtue of the rebounds and
     entanglements of atoms, it would be certainly better to maintain
     that the kidneys have no attractive action at all; for his theory,
     when examined, would be found as it stands to be much more
     ridiculous even than the theory of the lodestone, mentioned a
     little while ago. Attraction occurs in the way that Hippocrates
     laid down; this will be stated more clearly as the discussion
     proceeds; for the present our task is not to demonstrate this, but
     to point out that no other cause of the secretion of urine can be
     given except that of attraction by the kidneys, and that this
     attraction does not take place in the way imagined by people who
     do not allow Nature a faculty of her own.

     For if it be granted that there is any attractive faculty at all
     in those things which are governed by Nature, a person who
     attempted to say anything else about the absorption of nutriment
     would be considered a fool.

     16. Now, while Erasistratus for some reason replied at great
     length to certain other foolish doctrines, he entirely passed over
     the view held by Hippocrates, not even thinking it worth while to
     mention it, as he did in his work "On Deglutition"; in that work,
     as may be seen, he did go so far as at least to make mention of
     the word attraction, writing somewhat as follows:

     "Now, the stomach does not appear to exercise any attraction." But
     when he is dealing with anadosis he does not mention the
     Hippocratic view even to the extent of a single syllable. Yet we
     should have been satisfied if he had even merely written this:
     "Hippocrates lies in saying 'The flesh attracts both from the
     stomach and from without,' for it cannot attract either from the
     stomach or from without." Or if he had thought it worth while to
     state that Hippocrates was wrong in criticizing the weakness of
     the neck of the uterus, "seeing that the orifice of the uterus has
     no power of attracting semen," or if he [Erasistratus] had thought
     proper to write any other similar opinion, then we in our turn
     would have defended ourselves in the following terms:

     "My good sir, do not run us down in this rhetorical fashion
     without some proof; state some definite objection to our view, in
     order that either you may convince us by a brilliant refutation of
     the ancient doctrine, or that, on the other hand, we may convert
     you from your ignorance." Yet why do I say "rhetorical"? For we
     too are not to suppose that when certain rhetoricians pour
     ridicule upon that which they are quite incapable of refuting,
     without any attempt at argument, their words are really thereby
     constituted rhetoric. For rhetoric proceeds by persuasive
     reasoning; words without reasoning are buffoonery rather than
     rhetoric. Therefore, the reply of Erasistratus in his treatise "On
     Deglutition" was neither rhetoric nor logic. For what is it that
     he says? "Now, the stomach does not appear to exercise any
     traction." Let us testify against him in return, and set our
     argument beside his in the same form. Now, there appears to be no
     peristalsis of the gullet. "And how does this appear?" one of his
     adherents may perchance ask. "For is it not indicative of
     peristalsis that always when the upper parts of the gullet
     contract the lower parts dilate?" Again, then, we say, "And in
     what way does the attraction of the stomach not appear? For is it
     not indicative of attraction that always when the lower parts of
     the gullet dilate the upper parts contract?" Now, if he would but
     be sensible and recognize that this phenomenon is not more
     indicative of the one than of the other view, but that it applies
     equally to both, we should then show him without further delay the
     proper way to the discovery of truth.

     We will, however, speak about the stomach again. And the dispersal
     of nutriment [anadosis] need not make us have recourse to the
     theory regarding the natural tendency of a vacuum to become
     refilled, when once we have granted the attractive faculty of the
     kidneys. Now, although Erasistratus knew that this faculty most
     certainly existed, he neither mentioned it nor denied it, nor did
     he make any statement as to his views on the secretion of urine.

     Why did he give notice at the very beginning of his "General
     Principles" that he was going to speak about natural activities-
     firstly what they are, how they take place, and in what
     situations- and then, in the case of urinary secretion, declared
     that this took place through the kidneys, but left out its method
     of occurrence? It must, then, have been for no purpose that he
     told us how digestion occurs, or spends time upon the secretion of
     biliary superfluities; for in these cases also it would have been
     sufficient to have named the parts through which the function
     takes place, and to have omitted the method. On the contrary, in
     these cases he was able to tell us not merely through what organs,
     but also in what way it occurs- as he also did, I think, in the
     case of anadosis; for he was not satisfied with saying that this
     took place through the veins, but he also considered fully the
     method, which he held to be from the tendency of a vacuum to
     become refilled. Concerning the secretion of urine, however, he
     writes that this occurs through the kidneys, but does not add in
     what way it occurs. I do not think he could say that this was from
     the tendency of matter to fill a vacuum, for, if this were so,
     nobody would have ever died of retention of urine, since no more
     can flow into a vacuum than has run out. For, if no other factor
     comes into operation save only this tendency by which a vacuum
     becomes refilled, no more could ever flow in than had been
     evacuated. Nor, could he suggest any other plausible cause, such,
     for example, as the of nutriment by the stomach which occurs in
     the process of anadosis; this had been entirely disproved in the
     case of blood in the vena cava; it is excluded, not merely owing
     to the long distance, but also from the fact that the overlying
     heart, at each diastole, robs the vena cava by violence of a
     considerable quantity of blood.

     In relation to the lower part of the vena cava there would still
     remain, solitary and abandoned, the specious theory concerning the
     filling of a vacuum. This, however, is deprived of plausibility by
     the fact that people die of retention of urine, and also, no less,
     by the situation of the kidneys. For, if the whole of the blood
     were carried to the kidneys, one might properly maintain that it
     all undergoes purification there. But, as a matter of fact, the
     whole of it does not go to them, but only so much as can be
     contained in the veins going to the kidneys; this portion only,
     therefore, will be purified. Further, the thin serous part of this
     will pass through the kidneys as if through a sieve, while the
     thick sanguineous portion remaining in the veins will obstruct the
     blood flowing in from behind; this will first, therefore, have to
     run back to the vena cava, and so to empty the veins going to the
     kidneys; these veins will no longer be able to conduct a second
     quantity of unpurified blood to the kidneys- occupied as they are
     by the blood which had preceded, there is no passage left. What
     power have we, then, which will draw back the purified blood from
     the kidneys? And what power,in the next place, will bid this blood
     retire to the lower part of the vena cava, and will enjoin on
     another quantity coming from above not to proceed downwards before
     turning off into the kidneys?

     Now Erasistratus realized that all these ideas were open to many
     objections, and he could only find one idea which held good in all
     respects- namely, that of attraction. Since, therefore, he did not
     wish either to get into difficulties or to mention the view of
     Hippocrates, he deemed it better to say nothing at all as to the
     manner in which secretion occurs.

     But even if he kept silence, I am not going to do so. For I know
     that if one passes over the Hippocratic view and makes some other
     pronouncement about the function of the kidneys, one cannot fall
     to make oneself utterly ridiculous. It was for this reason that
     Erasistratus kept silence and Asclepiades lied; they are like
     slaves who have had plenty to say in the early part of their
     career, and have managed by excessive rascality to escape many and
     frequent accusations, but who, later, when caught in the act of
     thieving, cannot find any excuse; the more modest one then keeps
     silence, as though thunderstruck, whilst the more shameless
     continues to hide the missing article beneath his arm and denies
     on oath that he has ever seen it. For it was in this way also that
     Asclepiades, when all subtle excuses had failed him and there was
     no longer any room for nonsense about "conveyance towards the
     rarefied part [of the air]," and when it was impossible without
     incurring the greatest derision to say that this superfluity [i.e.
     the urine] is generated by the kidneys as is bile by the canals in
     the liver- he, then, I say, clearly lied when he swore that the
     urine does not reach the kidneys, and maintained that it passes,
     in the form of vapour, straight from the region of the vena cava,
     to collect in the bladder.

     Like slaves, then, caught in the act of stealing, these two are
     quite bewildered, and while the one says nothing, the other
     indulges in shameless lying.

     17. Now such of the younger men as have dignified themselves with
     the names of these two authorities by taking the appellations
     "Erasistrateans" or "Asclepiadeans" are like the Davi and Getae-
     the slaves introduced by the excellent Menander into his comedies.
     As these slaves held that they had done nothing fine unless they
     had cheated their master three times, so also the men I am
     discussing have taken their time over the construction of impudent
     sophisms, the one party striving to prevent the lies of
     Asclepiades from ever being refuted, and the other saying stupidly
     what Erasistratus had the sense to keep silence about.

     But enough about the Asclepiadeans. The Erasistrateans, in
     attempting to say how the kidneys let the urine through, will do
     anything or suffer anything or try any shift in order to find some
     plausible explanation which does not demand the principle of

     Now those near the times of Erasistratus maintain that the parts
     above the kidneys receive pure blood, whilst the watery residue,
     being heavy, tends to run downwards; that this, after percolating
     through the kidneys themselves, is thus rendered serviceable, and
     is sent, as blood, to all the parts below the kidneys.

     For a certain period at least this view also found favour and
     flourished, and was held to be true; after a time, however, it
     became suspect to the Erasistrateans themselves, and at last they
     abandoned it. For apparently the following two points were
     assumed, neither of which is conceded by anyone, nor is even
     capable of being proved. The first is the heaviness of the serous
     fluid, which was said to be produced in the vena cava, and which
     did not exist, apparently, at the beginning, when this fluid was
     being carried up from the stomach to the liver. Why, then, did it
     not at once run downwards when it was in these situations? And if
     the watery fluid is so heavy, what plausibility can anyone find in
     the statement that it assists in the process of anadosis?

     In the second place there is this absurdity, that even if it be
     agreed that all the watery fluid does fall downwards, and only
     when it is in the vena cava, still it is difficult, or, rather,
     impossible, to say through what means it is going to fall into the
     kidneys, seeing that these are not situated below, but on either
     side of the vena cava, and that the vena cava is not inserted into
     them, but merely sends a branch into each of them, as it also does
     into all the other parts.

     What doctrine, then, took the place of this one when it was
     condemned? One which to me seems far more foolish than the first,
     although it also flourished at one time. For they say, that if oil
     be mixed with water and poured upon the ground, each will take a
     different route, the one flowing this way and the other that, and
     that, therefore, it is not surprising that the watery fluid runs
     into the kidneys, while the blood falls downwards along the vena
     cava. Now this doctrine also stands already condemned. For why, of
     the countless veins which spring from the vena cava, should blood
     flow into all the others, and the serous fluid be diverted to
     those going to the kidneys? They have not answered the question
     which was asked; they merely state what happens and imagine they
     have thereby assigned the reason.

     Once again, then (the third cup to the Saviour!), let us now speak
     of the worst doctrine of all, lately invented by Lycus of
     Macedonia, but which is popular owing to its novelty. This Lycus,
     then, maintains, as though uttering an oracle from the inner
     sanctuary, that urine is residual matter from the nutrition of the
     kidneys! Now, the amount of urine passed every day shows clearly
     that it is the whole of the fluid drunk which becomes urine,
     except for that which comes away with the dejections or passes off
     as sweat or insensible perspiration. This is most easily
     recognized in winter in those who are doing no work but are
     carousing, especially if the wine be thin and diffusible; these
     people rapidly pass almost the same quantity as they drink. And
     that even Erasistratus was aware of this is known to those who
     have read the first book of his "General Principles." Thus Lycus
     is speaking neither good Erasistratism, nor good Asclepiadism, far
     less good Hippocratism. He is, therefore, as the saying is, like a
     white crow, which cannot mix with the genuine crows owing to its
     colour, nor with the pigeons owing to its size. For all this,
     however, he is not to be disregarded; he may, perhaps, be stating
     some wonderful truth, unknown to any of his predecessors.

     Now it is agreed that all parts which are undergoing nutrition
     produce a certain amount of residue, but it is neither agreed nor
     is it likely, that the kidneys alone, small bodies as they are,
     could hold four whole congii, and sometimes even more, of residual
     matter. For this surplus must necessarily be greater in quantity
     in each of the larger viscera; thus, for example, that of the
     lung, if it corresponds in amount to the size of the viscus, will
     obviously be many times more than that in the kidneys, and thus
     the whole of the thorax will become filled, and the animal will be
     at once suffocated. But if it be said that the residual matter is
     equal in amount in each of the other parts, where are the
     bladders, one may ask, through which it is excreted? For, if the
     kidneys produce in drinkers three and sometimes four congii of
     superfluous matter, that of each of the other viscera will be much
     more, and thus an enormous barrel will be needed to contain the
     waste products of them all. Yet one often urinates practically the
     same quantity as one has drunk, which would show that the whole of
     what one drinks goes to the kidneys.

     Thus the author of this third piece of trickery would appear to
     have achieved nothing, but to have been at once detected, and
     there still remains the original difficulty which was insoluble by
     Erasistratus and by all others except Hippocrates. I dwell
     purposely on this topic, knowing well that nobody else has
     anything to say about the function of the kidneys, but that either
     we must prove more foolish than the very butchers if we do not
     agree that the urine passes through the kidneys; or, if one
     acknowledges this, that then one cannot possibly give any other
     reason for the secretion than the principle of attraction.

     Now, if the movement of urine does not depend on the tendency of a
     vacuum to become refilled, it is clear that neither does that of
     the blood nor that of the bile; or if that of these latter does
     so, then so also does that of the former. For they must all be
     accomplished in one and the same way, even according to
     Erasistratus himself.

     This matter, however, will be discussed more fully in the book
     following this.