BIBLIOGRAPHY

1On the Affections of the Mind, p. 41 (Kühn’s ed.).

2“Averrhoës who made the great Commentary” (Dante). It was Averrhoës (Ebn Roshd) who, in the 12th century, introduced Aristotle to the Mohammedan world, and the “Commentary” referred to was on Aristotle.

3What appear to me to be certain resemblances between the Galenical and the modern vitalistic views of Henri Bergson may perhaps be alluded to here. Galen’s vital principle, ἡ τεχνικὴ φύσις (“creative growth”), presents analogies withl’Evolution créatrice: both manifest their activity in producing qualitative change (ἀλλοίωσις,changement): in both, the creative change cannot be analysed into a series of static states, but is one and continuous. In Galen, however, it comes to an end with thedevelopment of the individual, whereas in Bergson it continues indefinitely as theevolution of life. The three aspects of organic life may be tabulated thus:—δύναμιςἐνέργειαἔργονWork to be done.Work being done.Work done, finished.Future aspect.Present aspect.Past aspect.Function.Structure.Theélan vital.A “thing.”A changing which cannot be understood as a sum of static parts; a constant becoming, never stopping—at least till the ἔργον is reached.Bergson’s “teleological” aspect.Bergson’s “philosophical” aspect.Bergson’s “outlook of physical science.”Galen recognized “creativeness” (τέχνη) in thedevelopmentof the individual and its parts (ontogeny) and in the maintenance of these, but he failed to appreciate the creativeevolutionof species (phylogeny), which is, of course, part of the same process. To the teleologist the possibilities (δυνάμεις) of the Physis are limited, to Bergson they are unlimited. Galen and Bergson agree in attaching most practical importance to the middle category—that of Function.While it must be conceded that Galen, following Aristotle, had never seriously questioned the fixity of species, the following quotation from his workOn Habits(chap. ii.) will show that he must have at least had occasional glimmerings of our modern point of view on the matter. Referring toassimilation, he says: “Just as everything we eat or drink becomesaltered in quality, so of course also does the altering factor itself become altered.... A clear proof of the assimilation of things which are being nourished to that which is nourishing them is the change which occurs in plants and seeds; this often goes so far that what is highly noxious in one soil becomes, when transplanted into another soil, not merely harmless, but actually useful. This has been largely put to the test by those who compose memoirs on farming and on plants, as also by zoological authors who have written on the changes which occur according to the countries in which animals live. Since, therefore, not only is the nourishment altered by the creature nourished, but the latter itself also undergoes some slight alteration,this slight alteration must necessarily become considerable in the course of time, and thus properties resulting from prolonged habit must come to be on a par with natural properties.”Galen fails to see the possibility that the “natural” properties themselves originated in this way, as activities which gradually became habitual—that is to say, that the effects ofnurturemay become a “second nature,” and so eventuallynatureitself.The whole passage, however, may be commended to modern biologists—particularly, might one say, to those bacteriologists who have not yet realised how extraordinarilyrelativeis the term “specificity” when applied to the subject-matter of their science.

A changing which cannot be understood as a sum of static parts; a constant becoming, never stopping—at least till the ἔργον is reached.

Bergson’s “teleological” aspect.

Bergson’s “philosophical” aspect.

Bergson’s “outlook of physical science.”

Galen recognized “creativeness” (τέχνη) in thedevelopmentof the individual and its parts (ontogeny) and in the maintenance of these, but he failed to appreciate the creativeevolutionof species (phylogeny), which is, of course, part of the same process. To the teleologist the possibilities (δυνάμεις) of the Physis are limited, to Bergson they are unlimited. Galen and Bergson agree in attaching most practical importance to the middle category—that of Function.

While it must be conceded that Galen, following Aristotle, had never seriously questioned the fixity of species, the following quotation from his workOn Habits(chap. ii.) will show that he must have at least had occasional glimmerings of our modern point of view on the matter. Referring toassimilation, he says: “Just as everything we eat or drink becomesaltered in quality, so of course also does the altering factor itself become altered.... A clear proof of the assimilation of things which are being nourished to that which is nourishing them is the change which occurs in plants and seeds; this often goes so far that what is highly noxious in one soil becomes, when transplanted into another soil, not merely harmless, but actually useful. This has been largely put to the test by those who compose memoirs on farming and on plants, as also by zoological authors who have written on the changes which occur according to the countries in which animals live. Since, therefore, not only is the nourishment altered by the creature nourished, but the latter itself also undergoes some slight alteration,this slight alteration must necessarily become considerable in the course of time, and thus properties resulting from prolonged habit must come to be on a par with natural properties.”

Galen fails to see the possibility that the “natural” properties themselves originated in this way, as activities which gradually became habitual—that is to say, that the effects ofnurturemay become a “second nature,” and so eventuallynatureitself.

The whole passage, however, may be commended to modern biologists—particularly, might one say, to those bacteriologists who have not yet realised how extraordinarilyrelativeis the term “specificity” when applied to the subject-matter of their science.

4In terms of filtration, diffusion, and osmosis.

Pg xli-xlii

Bibliothèque Nationale. Paris. No. 2267.Library of St. Mark. Venice. No. 275.

Arabic translations by Honain in the Escurial Library, and in the Library at Leyden. Hebrew translation in the Library at Bonn. Latin translations in the Library of Gonville and Caius College (MSS.), No. 947; also by Linacre in editions published, London, 1523; Paris, 1528; Leyden, 1540, 1548, and 1550; also by C.G. Kühn, Leipzig, 1821.

Nic. de Anglia in Bib. Nat. Paris (MSS.), No. 7015; J. Rochon,ibidem, No. 7025; J. Segarra, 1528; J. Sylvius, 1550, 1560; L. Joubert, 1599; M. Sebitz, 1644, 1645; J.B. Pacuvius, 1554; J.C.G. Ackermann, 1821, in the introduction to Kühn’s translation, p. lxxx; Ilberg in articles on “Die Schriftstellerei des Klaudios Galenos,” inRhein. Mus., Nos. 44, 47, 51, and 52 (years 1889, 1892, 1896 and 1897); I. von Mueller inQuæstiones Criticae de Galeni libris, Erlangen, 1871; Steinschneider in Virchow’sArchiv, No. cxxiv. for 1891; Wenrich inDe auctorum graecorum versionibus et commentariis syriacis, arabicis, armiacis, persisque, Leipzig, 1842.

Pg xliii

Distinction between the effects of (a) the organism’spsycheor soul (b) itsphysisor nature. The author proposes to confine himself to a consideration of the latter—the vegetative—aspect of life.

Definition of terms. Different kinds ofmotion.Alterationor qualitative change. Refutation of the Sophists’ objection that such change is only apparent, not real. The four fundamental qualities of Hippocrates (later Aristotle). Distinction betweenfaculty,activity(function), andeffect(work or product).

It is by virtue of thefour qualitiesthat each part functions. Some authorities subordinate the dry and the moist principles to the hot and the cold. Aristotle inconsistent here.

We must suppose that there arefacultiescorresponding in number to the visibleeffects(or products) with which we are familiar.

Genesis, growth, and nutrition. Genesis (embryogeny) sub-divided into histogenesis and organogenesis. Growth is a tridimensional expansion of the solid parts formed during genesis. Nutrition.

Pg xliv

The process of genesis (embryogeny) from insemination onwards. Each of the simple, elementary, homogeneous parts (tissues) is produced by a special blend of the four primary alterative faculties (such secondary alterative faculties beingostopoietic,neuropoietic, etc.). A specialfunctionandusealso corresponds to each of these special tissues. The bringing of these tissues together intoorgansand the disposal of these organs is performed by another faculty calleddiaplastic,moulding, orformative.

We now pass from genesis togrowth. Growth essentially a post-natal process; it involves two factors, expansion and nutrition, explained by analogy of a familiar child’s game.

Nutrition.

These three primary faculties (genesis, growth, nutrition) have various others subservient to them.

Nutrition not a simple process. (1) Need of subsidiary organs for the various stages of alteration,e.g., of bread into blood, of that into bone, etc. (2) Need also of organs for excreting the non-utilizable portions of the food,e.g., much vegetable matter is superfluous. (3) Need of organs of a third kind, for distributing the pabulum through the body.

Nutrition analysed into the stages of application (prosthesis), adhesion (prosphysis), and assimilation. The stages illustrated by certain pathological conditions. Different shades of meaning of the termnutriment.

Pg xlv

The two chief medico-philosophical schools—Atomist and Vitalist. Hippocrates an adherent of the latter school—his doctrine of an original principle or “nature” in every living thing (doctrine of the unity of the organism).

Failure of Asclepiades to understand the functions of kidneys and ureters. His hypothesis of vaporization of imbibed fluids is here refuted. A demonstration of urinary secretion in the living animal; the forethought and artistic skill of Nature vindicated. Refutation also of Asclepiades’s disbelief in the special selective action of purgative drugs.

While Asclepiades deniesin totothe obvious fact of specific attraction, Epicurus grants the fact, although his attempt to explain it by the atomic hypothesis breaks down. Refutation of the Epicurean theory of magnetic attraction. Instances of specific attraction of thorns and animal poisons by medicaments, of moisture by corn, etc.

It now being granted that the urine is secreted by the kidneys, therationaleof this secretion is enquired into. The kidneys are not mechanical filters, but are by virtue of theirnaturepossessed of a specific faculty of attraction.

Erasistratus, again, by his favourite principle ofhorror vacuicould never explain the secretion of urine by the kidneys. While, however, he acknowledged that the kidneys do secrete urine, he makes no attempt to explain this; he ignores, but does not attempt to refute, the Hippocratic doctrine of specificattraction. “Servile” position taken up by Asclepiades and Erasistratus in regard to this function of urinary secretion.

Pg xlvi

Three other attempts (by adherents of the Erasistratean school and by Lycus of Macedonia) to explain how the kidneys come to separate out urine from the blood. All these ignore the obvious principle of attraction.

In order to explain dispersal of food from alimentary canalviâthe veins (anadosis) there is no need to invoke with Erasistratus, thehorror vacui, since here again the principle of specific attraction is operative; moreover, blood is also driven forward by the compressing action of the stomach and the contractions of the veins. Possibility, however, of Erasistratus’s factor playing a certain minorrôle.

The Erasistratean idea that bile becomes separated out from the blood in the liver because, being the thinner fluid, it alone can enter the narrow stomata of the bile-ducts, while the thicker blood can only enter the wider mouths of the hepatic venules.

The morphological factors suggested by Erasistratus are quite inadequate to explain biological happenings. Erasistratus inconsistent with his own statements. The immanence of thephysisor nature; her shaping is not merely external like that of a statuary, but involves the entire substance. In genesis (embryogeny) the semen is the active, and the menstrual blood the passive, principle. Attractive, alterative, and formative faculties of the semen. Embryogeny is naturally followed by growth; these two functions distinguished.

Pg xlvii

Unjustified claim by Erasistrateans that their founder had associations with the Peripatetic (Aristotelian) school. The characteristic physiological tenets of that school (which were all anticipated by Hippocrates) in no way agree with those of Erasistratus, save that both recognize the purposefulness of Nature; in practice, however, Erasistratus assumed numerous exceptions to this principle. Difficulty of understanding why he rejected the biological principle of attraction in favour of anatomical factors.

A further difficulty raised by Erasistratus’s statement regarding secretion of bile in the liver.

The same holds with nutrition. Even if we grant that veins may obtain their nutrient blood by virtue of thehorror vacui(chap. i.), how could this explain the nutrition of nerves? Erasistratus’s hypothesis of minute elemental nerves and vessels within the ordinary visible nerves simply throws the difficulty further back. And is Erasistratus’s minute “simple” nerve susceptible of further analysis, as the Atomists would assume? If so, this is opposed to the conception of a constructive and artistic Nature which Erasistratus himself shares with Hippocrates and the writer. And if his minute nerve is really elementary and not further divisible, then it cannot, according to his own showing, contain a cavity; therefore thehorror vacuidoes not apply to it. And how could this principle apply to the restoration to its original bulk of a part which had become thin through disease, where more matter must become attached than runs away? A quotation from Erasistratus shows that he did acknowledge an “attraction,” although not exactly in the Hippocratic sense.

Pg xlviii

In the last resort, the ultimate living elements (Erasistratus’ssimple vessels) must draw in their food by virtue of an inherent attractive faculty like that which the lodestone exerts on iron. Thus the process of anadosis, from beginning to end, can be explained without assuming ahorror vacui.

Erasistratus’s disregard for the humours. In respect to excessive formation of bile, however, prevention is better than cure: accordingly we must consider its pathology. Does blood pre-exist in the food, or does it come into existence in the body? Erasistratus’s purely anatomical explanation ofdropsy. He entirely avoids the question of the four qualities (e.g.the importance of innate heat) in the generation of the humours, etc. Yet the problem of blood-production is no less important than that of gastric digestion. Proof that bile does not pre-exist in the food. The four fundamental qualities of Hippocrates and Aristotle. How the humours are formed from food taken into the veins: when heat is in proportionate amount, blood results; when in excess, bile; when deficient, phlegm. Various conditions determining cold or warm temperaments. The four primary diseases result each from excess of one of the four qualities. Erasistratus unwillingly acknowledges this when he ascribes the indigestion occurring in fever toimpaired functionof the stomach. For what causes thisfunctio laesa? Proof that it is the fever (excess of innate heat).If, then, heat plays so important a part in abnormal functioning, so must it also in normal (i.e.causes of eucrasia involved in those of dyscrasia, of physiology in those of pathology). A like argument explains thegenesis of the humours. Addition of warmth to things already warm makes them bitter; thus honey turns to bile in people who are already warm; where warmth deficient, as in old people, it turns to useful blood. This is a proof that bile does not pre-exist, as such, in the food.

Pg xlix

Thefunctions of organsalso depend on the way in which the four qualities are mixed—e.g.the contracting function of the stomach. Treatment only possible when we know thecausesof errors of function. The Erasistrateans practically Empiricists in this respect. On an appreciation of the meaning of adyscrasiafollows naturally the Hippocratic principle of treating opposites by opposites (e.g.cooling the over-heated stomach, warming it when chilled, etc.). Useless in treatment to know merely the function of each organ; we must know thebodily conditionwhich upsets this function. Blood is warm and moist. Yellow bile is warm and (virtually, though not apparently) dry. Phlegm is cold and moist. The fourth possible combination (cold and dry) is represented byblack bile. For the clearing out of this humour from the blood, Nature has provided the spleen—an organ which, according to Erasistratus, fulfils no purpose. Proof of the importance of the spleen is the jaundice, toxaemia, etc., occurring when it is diseased. Erasistratus’s failure to mention the views of leading authorities on this organ shows the hopelessness of his position. The Hippocratic view has now been demonstrated deductively and inductively. The classical view as to the generation of the humours. Normal and pathological forms of yellow and black bile. Part played by theinnate heatin their production. Other kinds of bile are merely transition-stages between these extreme types. Abnormal forms removed by liver and spleen respectively. Phlegm, however, does not need a special excretory organ, as it can undergo entire metabolism in the body.Need for studying the works of the Ancients carefully, in order to reach a proper understanding of this subject.

Pg l

A recapitulation of certain points previously demonstrated. Every part of the animal has an attractive and an alterative (assimilative) faculty; it attracts the nutrient juice which is proper to it. Assimilation is preceded by adhesion (prosphysis) and that again, by application (prosthesis). Application the goal of attraction. It would not, however, be followed by adhesion and assimilation if each part did not also possess a faculty forretaining in positionthe nutriment which has been applied.A priorinecessity for thisretentivefaculty.

The same faculty to be proveda posteriori. Its correspondingfunction(i.e.the activation of this faculty or potentiality) well seen in the large hollow organs, notably the uterus and stomach.

Exercise of the retentive faculty particularly well seen in the uterus. Its object is to allow the embryo to attain full development; this being completed, a new faculty—the expulsive—hitherto quiescent, comes into play. Characteristic signs and symptoms of pregnancy. Tight grip of uterus on growing embryo, and accurate closure of os uteri during operation of the retentive faculty. Dilatation of os and expulsive activities of uterus at full term, or when foetus dies. Prolapse from undue exercise of this faculty.Rôleof the midwife. Accessory muscles in parturition.

Same two faculties seen in stomach.Gurglingsorborborygmishow that this organ is weak and is not gripping its contents tightly enough. Undue delay of food in a weakPg listomach proved not to be due to narrowness of pylorus: length of stay depends on whetherdigestion(another instance of the characteristically vital process ofalteration) has taken place or not. Erasistratus wrong in attributing digestion merely to the mechanical action of the stomach walls. When digestion completed, then pylorus opens and allows contents to pass downwards, just as os uteri when development of embyro completed.

If attraction and elimination always proceededpari passu, the content of these hollow organs (including gall-bladder and urinary bladder) would never vary in amount. Aretentivefaculty, therefore, also logically needed. Its existence demonstrated. Expulsion determined by qualitative and quantitative changes of contents. “Diarrhoea” of stomach. Vomiting.

Every organic part has anappetiteandaversionfor the qualities which are appropriate and foreign to it respectively. Attraction necessarily leads to a certainbenefitreceived. This again necessitatesretention.

Interaction between two bodies; the stronger masters the weaker; a deleterious drug masters the forces of the body, whereas food is mastered by them; this mastery is analteration, and the amount of alteration varies with the different organs; thus a partial alteration is effected in mouth by saliva, but much greater in stomach, where not only gastric juice, but also bile, pneuma, innate heat (i.e.oxidation?), and other powerful factors are brought to bear on it; need of considerable alteration in stomachPg liias a transition-stage between food and blood; appearance of faeces in intestine another proof of great alteration effected in stomach. Asclepiades’s denial of real qualitative change in stomach rebutted. Erasistratus’s denial that digestion in any way resembles aboilingprocess comes from his taking words too literally.

Erasistratus denies that the stomach exerts any pull in the act of swallowing. That he is wrong, however, is proved by the anatomical structure of the stomach—its inner coat with longitudinal fibres obviously acts as avis a fronte(attraction), whilst its outer coat exercises through the contraction of its circular fibres avis a tergo(propulsion); the latter also comes into play in vomiting. The stomach uses the oesophagus as a kind of hand, to draw in its food with. The functions of the two coats proved also by vivisection. Swallowing cannot be attributed merely to the force of gravity.

These four faculties which subserve nutrition are thus apparent in many different parts of the body.

Need for elaborating the statements of the ancient physicians. Superiority of Ancients to Moderns. This state of affairs can only be rectified by a really efficient education of youth. The chief requisites of such an education.

For the sake of the few who realty wish truth, the argument will be continued. A third kind of fibre—theoblique—subservesretention; the way in which this fibre is disposed in different coats.

Pg liii

The factor which brings the expulsive faculty into action is essentially a condition of the organ or its contents which is the reverse of that which determined attraction. Analogy between abortion and normal parturition. Whatever producesdiscomfortmust be expelled. That discomfort also determines expulsion of contents from gall-bladder is not so evident as in the case of stomach, uterus, urinary bladder, etc., but can be logically demonstrated.

Expulsion takes place through the same channel as attraction (e.g., in stomach, gall-bladder, uterus). Similarly the delivery (anadosis) of nutriment to the liver from the food-canalviâthe mesenteric veins may have its direction reversed. Continuous give-and-take between different parts of the body; superior strength of certain parts is natural, of others acquired. When liver contains abundant food and stomach depleted, latter may draw on former; this occurs when animal can get nothing to eat, and so prevents starvation. Similarly, when one part becomes over-distended, it tends to deposit its excess in some weaker part near it; this passes it on to some still weaker part, which cannot get rid of it; hencedepositsof various kinds. Further instances of reversal of the normal direction of anadosis from the food canal through the veins. Such reversal of functions would in any case be expecteda priori. In the vomiting of intestinal obstruction, matter may be carried backwards all the way from the intestine to the mouth; not surprising, therefore, that, under certain circumstances, food-material might be driven right back from the skin-surface to the alimentary canal (e.g.in excessive chilling of surface); not much needed to determine this reversal of direction. Action of purgative drugs upon terminals of veins; one part draws from another until whole body participates; similarly in intestinal obstruction, each part passes on the irritating substance to its weakerPg livneighbour. Reversal of direction of flow occurs not merely on occasion but also constantly (as in arteries, lungs, heart, etc.). The various stages of normal nutrition described. Why the stomach sometimes draws back the nutriment it had passed on to portal veins and liver. A similar ebb and flow in relation to the spleen. Comparison of the parts of the body to a lot of animals at a feast. The valves of the heart are a provision of Nature to prevent this otherwise inevitable regurgitation, though even they are not quite efficient.

The superficial arteries, when they dilate, draw in air from the atmosphere, and the deeper ones a fine, vaporous blood from the veins and heart. Lighter matter such as air will always be drawn in preference to heavier; this is why the arteries in the food-canal draw in practically none of the nutrient matter contained in it.

The two kinds of attraction—the mechanical attraction of dilating bellows and the “physical” (vital) attraction by living tissue of nutrient matter which is specifically allied or appropriate to it. The former kind—that resulting fromhorror vacui—acts primarily on light matter, whereas vital attraction has no essential concern with such mechanical factors. A hollow organ exercises, by virtue of its cavity, the former kind of attraction, and by virtue of the living tissue of its walls, the second kind. Application of this to question of contents of arteries;anastomoses of arteries and veins.Foramina in interventricular septum of heart, allowing some blood to pass from right to left ventricle. Large size of aorta probably due to fact that it not merely carries the pneuma received from the lungs, but also some of the blood which percolates through septum from right ventricle. Thus arteries carry not merely pneuma, but also some light vaporous blood, which certain parts need morePg lvthan the ordinary thick blood of the veins. The organic parts must have their blood-supply sufficiently near to allow them to absorb it; comparison with an irrigation system in a garden. Details of the process of nutrition in the ultimate specific tissues; some are nourished from the blood directly; in others a series of intermediate stages must precede complete assimilation; for example, marrow is an intermediate stage between blood and bone.From the generalisations arrived at in the present work we can deduce the explanation of all kinds of particular phenomena; an instance is given, showing the co-operation of various factors previously discussed.

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 effects6of thesoul7and the latter as effects of thenature.8And 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 questionvegetative, and the othersensory, 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.

Thus we shall enquire, in the course of this treatise, from whatfacultiesthese 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 isat rest; but, if it departs from this in any respect we then say that in this respect itundergoes motion.9Accordingly, when it departs in various ways from its pre-existing 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 tocolour; 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 toflavour; to both of these instances, as well as to those previously mentioned, we shall apply the termqualitative 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 speakof its undergoing motion; similarly also when anything moist becomes dry, or dry moist. Now, the common term which we apply to all these cases isalteration.

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 istransference.10

These two kinds of motion, then, are simple and primary, while compounded from them we havegrowthanddecay,11as 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 aregenesisanddestruction,12genesis being a coming into existence,13and destruction being the opposite.

Now, common to all kinds of motion ischange from the pre-existing state, while common to all conditions of rest isretention of the pre-existing 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)14will have it that the qualities do exist in it, but that theyare unchangeable and immutable from eternity to eternity, and that these apparent alterations are brought about byseparationandcombination.

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”15by Aristotle, and after him by Chrysippus,16I 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, of 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 interactingqualities, 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 thesubstancesas well as theirqualitiesundergo 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;17for immediate purposes we onlyneed to recognize thecomplete alteration of substance. In this way, nobody will suppose that bread represents a kind of meeting-place18for 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;19before 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).20And clearly this disproves the view of those who consider the elements21unchangeable, 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 thefacultiesof Nature, and what is the effect which each naturallyproduces. Now, of course, I mean by an effect22that which has already come into existence and has been completed by theactivity23of these faculties—for example, blood, flesh, or nerve. Andactivityis the name I give to the active change ormotion, and thecauseof this I call afaculty. 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 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 anactivity, and that of the food and the bones asymptomoraffection,24since the first group undergoesalterationand the second group is merelytransported. One might, therefore, also speak of theactivityas aneffectof Nature25—for example, digestion, absorption,26blood-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.

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 whichthe four qualities27are 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 certaindiffusionsandcondensations.28This 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 two only? Of course, if anyone were to maintain that in the case of animals and plants the Warm and Cold aremoreactive, the Dry and Moistlessso, 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.”

The so-calledblood-making29faculty 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 afaculty. Thus we say that there exists in the veins a blood-making faculty, as also a digestive30faculty in the stomach, a pulsatile31faculty 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.

The effects of Nature, then, while the animal is still being formed in the womb, are all the differentpartsof 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 ofalterationand ofshaping.32That is to say, in order that bone, nerve, veins, and all other [tissues] may come into existence, theunderlying substancefrom which the animal springs must bealtered; 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 ashapingorformativeprocess.33One would be justified in calling this substance which undergoes alteration thematerialof the animal, just as wood is the material of a ship, and wax of an image.

Growthis 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).Nutritionis an addition to these, without expansion.

Let us speak then, in the first place, of Genesis, which, as we have said, results fromalterationtogether withshaping.

The seed having been cast into the womb or into the earth (for there is no difference),34then, 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,35and in all the other qualitieswhich naturally derive therefrom.36These 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-calledtangibledistinctions, 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.37And 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 itssensible elements. The namesensible elementsis given to all thehomogeneous38parts of the body, and these are to be detected not by any system, but by personal observation of dissections.39

Now Nature constructs bone, cartilage, nerve, membrane, ligament, vein, and so forth, at the first stage of the animal’s genesis,40employing 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 theblending of these, for example, the bone-producing, nerve-producing, and cartilage-producing faculties41(since for the sake of clearness these names must be used as well).

Now the peculiar42flesh 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 isa 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,43the substance remaining in each organ is, from the point of view of the senses, simple and elementary. As regards those organs consisting of two dissimilarcoats,44of which each is simple, of these organs the coats 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 thespecialalterative faculties in each animal are of the same number as the elementary parts45; and further, theactivitiesmust necessarily correspond each to one of the special parts, just as each part has its specialuse—for example, those ducts which extend from the kidneys into the bladder, and which are calledureters; for these are not arteries, since they do not pulsate nor do they consist of two coats; and theyare 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,46and 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,47the combination therewith of the structures which are inserted into them, the outgrowth into the intestine,48the shape of the inner cavities, and the like, have all been determined by a faculty which we call the shaping or formative faculty49; this faculty we also state to beartistic—nay, the best and highest art—doing everything for some purpose, so thatthere is nothing ineffective or superfluous, or capable of being better disposed. This, however, I shall demonstrate in my work “On the Use of Parts.”

Passing now to the faculty of Growth50let us first mention that this, too, is present in the foetusin uteroas is also the nutritive faculty, but that at that stage these two faculties are, as it were,handmaidsto those already mentioned,51and do not possess in themselves supreme authority. When, however, the animal52has 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 variouscoatswhich 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 clearness.

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 commongame 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 thatnutritionis 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 distendedin all directionsbelongs 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 form.

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

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 isnutrition, and its cause is thenutritive faculty. Of course, the kind of activity here involved is also analteration, but not an alteration like that occurring at the stage ofgenesis.53For 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 termedgenesis, and the latter,assimilation.

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 notyet touched upon any ofthe partsof 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.

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