Generation of Animals

Book IV, 725a-728a

From: Aristotle: Generation of Animals (Greek). With an English translation by Arthur Leslie Peck, William Heinemann, London 1943, pp. 82-101.

Aristotle (384-322 BC) was a Greek philospher whose work proved enormously influential until the late Middle Ages. He wrote 'On the Generation of Animals' at around 350 AD.

palette resembles that which he has actually used ; whereas everything that undergoes colliquescence gets destroyed and departs from its proper nature.(a) Here is a piece of evidence to show that semen is not a colliquescence but a residue ; the large animals produce but few young, while the small ones are prolific. Now in the large animals there must of necessity be more colliquescence and less residue, because most of the nourishment is used up to maintain the large bulk of their body, so that but little residue is produced. Further, no place has been assigned by Nature for colliquescence, but it runs about in the body wherever it can find a clear way for itself ; whereas there is a proper place for all the natural residues e.g. the lower intestine (b) is set apart for the residue from the solid nourishment, the bladder for that from the fluid, the upper intestine (c) for that from the useful nourishment, the uterus, pudenda, and breasts for the seminal residues—they run into these places, and collect there. As evidence of the truth of our statement about what semen is we can quote the actual facts, facts which directly remit from this residue's being of the nature described by us. Thus (I) though only a very small quantity of semen be emitted, the exhaustion which follows is quite conspicuous (d) which suggests that the body is being deprived of the final product formed out of the nourishment. (There are, I know, a few who for a short period during the heat of youth derive relief from the emission of the semen when it is superabundant. The same is true also of nourishment in its first stage, if there is an excessive quantity of it ;

(d) Cf. Hippocrates, π. γονής 1 (vii. 470 Littre), quoted in note on 725 a 1.


the body is more comfortable for having got rid of it. Relief is obtained too when other residues are got rid of in company with the semen : in such cases what is emitted is not merely semen, but there are other substances which come away at the same time mixed up with it, and these are morbid. This explains why at certain times with some persons the emission is infertile : it contains so small an amount of actual semen. However, speaking generally for the majority of men, the sequel to sexual intercourse is exhaustion and weakness rather than relief, and the cause is as I have described.) Besides (2), semen is absent during childhood, old age, and infirmity ; absent during infirmity on account of the weakness of the body, during old age because the organism does not concoct a sufficient amount ; during child hood because the body is growing, and the concocted matter is all used up so soon that there is none left over : it is usually held that in about five years human beings, at any rate, grow to one-half of the complete size that they will attain in the rest of their lifetime. In respect of semen we find that with many animals and plants one group differs from another group, and even within one and the same group individuals of the same kind differ from each other, e.g., one man from another, and one grapevine from another. Some individuals have much semen, some little, some none at all; and this is not due to any bodily weak ness, but in some cases, at any rate, it is due to the opposite : the available supply gets used up to benefit the body ; as an example of this we have men in sound health putting on rather a lot of flesh (b) and getting a bit fat : these emit less semen and have less desire for sexual intercourse than is normal. A


similar phenomenon is that of grape-vines which go goaty," rampaging all over, the place because they are getting too much nourishment. (The reason the phrase " go goaty " is that they behave just like he-goats, which when they get fat indulge less in copulation, and incidentally this explains why goats are made to slim before the breeding season comes on.) And further it seems that fat people, men and women alike, are less fertile than those who are not fat, the reason being that when the body is too well fed, the effect of concoction upon the residue is to turn it into fat (since fat also is one of the residues, a healthy one, because it results from good living).

Some living things actually produce no semen at all: examples are the willow and the poplar; Both reasons together are responsible for this state of affairs ; in other words, on account of their weakness the trees cannot concoct their nourishment, and on account of their strength, they use it all up, as described above. Similarly, some animals are prolific and have abundance of semen because they are strong, but others because they are weak ; the explanation being that in the latter case much useless residue gets mixed up with the semen, and in some instances, when there is no clear way open by which the evacuated matter may leave, it actually produces disease, from which some recover though others succumb. Their semen is contaminated by the collequescences which get into it, just as they do into the urine—another malady by no means unknown;

(a) [Further, the same passage serves both for the residue and for the semen : (a) in those animals which

(29ff.); the latter part refers to the subjects discussed in 725 a—726 a.

produce residue both from the fluid nourishment and from the solid, the semen is discharged by the same exit as the fluid residue, because it is itself a residue from a fluid, the nourishment of all animals tending to be fluid rather than solid ; (b) in those animals which produce no fluid residue, the semen leaves by the same way as the solid excrement. Further, colliquescence is always morbid, whereas the removal of residue is beneficial; and the discharge of semen has both characteristics because it includes some of the useless nourishment. If it were just a colliquescence, it would always be injurious, whereas in fact it is not so.]

To conclude : the foregoing discussion makes it clear that, whether all animals discharge semen.' or not, semen is a residue derived from useful nourishment, and not only that, but from useful nourishment in its final form.

Our next task is to determine what is the character of the nourishment from which this residue is derived and we must discuss the menstrual discharge as well, because this occurs in some of the Vivipara. By this means we shall be able to give a clear answer to the following questions : Does the female discharge semen as the male does, which would mean that the object formed is a single mixture produced from two semens ; or is there no discharge of semen from the female ? And if there is none, then does the female contribute nothing whatever to generation, merely providing a place where generation may happen ; or does it contribute something else, and if so, how and in what manner does it do so ?

We have said before (a) that in blooded animals blood is the final form of the nourishment, and in


bloodless animals the analogous substance. And since semen also is a residue from nourishment — from nourishment in its final form, surely it follows that semen will be either blood or the analogous substance, or something formed out of these. Now every one of the parts (a) is formed out of the blood as it becomes concocted and in some way divided up into portions ; and though semen which has been concocted is by the time of its secretion from it considerably different in character from blood, yet unconcocted semen, and semen emitted under strain due to excessively frequent intercourse, has been known in some cases to have a bloodlike appearance when discharged ; and this shows that semen is pretty certainly a residue from that nourishment which is in the form of blood and which, 'as being the final form of nourishment, is distributed to the various parts of the body.(b) This, of course, is the reason why semen has great potency (c)— the loss of it from the system is just as exhausting as the loss of pure healthy blood — and this, too, is why we should expect children to resemble their parents : because there is a resemblance between that which is distributed to the various parts of the body and that which is left over.(d) Thus, the semen of the hand or of the face or of the whole animal really is hand or face or a whole animal though in an undifferentiated way ; in other words, what each of those is in actuality, such the semen is potentially ,(e) whether in respect of its own proper bulk, or because it has some dynamis (f) within itself (I mention both alternatives because from what we have said so far it is not clear which is the correct one, (g) i.e., whether

(g)This will be settled during the remaining; part of the Book ; see especially ch. 21.


the physical substance of the semen is the cause of generation, or whether, it contains some disposition and some principle of movement which effects, generation), since neither a hand nor any other part of the body whatsoever is a hand or any other part of the body if it lacks Soul (b) or some other dynamis; it has the same name,(c) but that is all.(d)

(e)[It is clear also that in cases where seminal colliquescence, occurs, this too is a residue; and this happens when (a fresh secretion) is decomposed into that which preceded it; just as when a (fresh) layer of plaster spread on a wall immediately drops away, the reason being that the stuff which comes away is identical with that which was applied in the first instance. In just the same way, the final residue is identical with the original colliquescence. Such then are the lines on which we treat that subject.] Now (1) the weaker creature too must of necessity produce a residue, greater in amount and less thoroughly concocted ; and (2) this, if such is its character, must of necessity be a volume of bloodlike fluid (3) That which by nature has a smaller share

κοινόν, ό ςε κατα τοϋνομα λόγος τής ουσίας έτερος In this case, the ουσία required to be present is Soul (see following note, and reference to De anima given in note on 738 b.26); but it is absent. For συνώνυμου, see note on 721 a. 3

(d) Because Soul is the essence of any particular body (or of any part of it). Cf. 738 b 26 and note there.

(e)This paragraph seems to be a continuation of the preceding interpolation, 726 a 25. There are variations in the text. Thus, the MSS. PSY replace " stuff which . . colliquescence " by " final residue is the same as the first residue." Some of the words seem to echo lines 14 and 15 above.

(f) Semen of course has undergone a further stage of concoction, and has lost its bloodlike appearance.


of heat is weaker ; and (4) the female answers to this description, as we have said already. From which we conclude that the bloodlike secretion which occurs in the female must of necessity be a residue just as much (as the secretion in the male). Of such a character is the discharge of what is called the menstrual fluid,

Thus much then is evident: the menstrual fluid is a residue, and it is the analogous thing in females to the semen in males. Its behaviour shows that this statement is correct. At the same time of life that semen begins to appear in males and is emitted, the menstrual discharge begins to flow in females, their voice changes and their breasts begin to become conspicuous ; and similarly, in the decline of life the power to generate ceases in males and the menstrual discharge ceases in females. Here are still further indications that this secretion which females produce is a residue. Speaking generally, unless the menstrual discharge is suspended, women are not troubled by haemorrhoids or bleeding from the nose or any other such discharge, and if it happens that they are, then the evacuations fall off in quantity, which suggests that the substance secreted is being drawn off to the other discharges, Again their blood vessels are not so prominent as those of males ; and females are more neatly made (a) and smoother than males, because the residue which goes to produce those characteristics in males is in females discharged together with the menstrual fluid. We are bound to hold, in addition, that for the same cause the bulk of the body in female Vivipara is smaller than that of the males, as of course it is only in Vivipara that the

(a) Also implying "hairless," " delicate," dainty."

menstrual discharge flows externally, and most conspicuously of all in women, who discharge a greater amount than any other female animals. On this account it is always very noticeable that the female is pale, and the blood-vessels are not prominent, and there is an obvious deficiency in physique as compared with males.

Now it is impossible that any creature should produce two seminal secretions, at once; and as the secretion in females which answers to semen in males is the menstrual fluid, it obviously follows that the female does not contribute any semen to generation ; for if there were semen, there would be no menstrual fluid ; but as menstrual fluid is in fact formed, therefore there is no semen.

We have said 'why it is that the menstrual fluid as well as semen is a residue. In support of this, there are a number of facts concerning animals which rnay be adduced; (1) Fat animals produce less semen than lean ones, as we said before, and the reason is that fat is a residue just as semen is, i.e., it is blood that has been concocted, only not in the same way as semen. Hence,it is not surprising that when the residue has been consumed to make fat the semen is deficient. Take a parallel from the bloodless animals: Cephalopods arid Crustacea are in their finest condition at the breeding season. Why ? Because, being bloodless, they produce no fat; hence, what in them corresponds to fat is at this period secreted into the seminal residue. (2) Here is an indication that the female does not discharge semen of the same kind as the male, and that the offspring is not formed from a mixture of two semens, as some allege. Very often the female conceives although she has derived


no pleasure from the act of coitus ; and, on the contrary side, when the female derives as much pleasure as the male, and they both keep the same pace, the female does not bear—unless there is a proper amount of menstrual liquid (as it is called) present. Thus, the female does not bear (a) if the menstrual fluid is completely absent, (b) if it is present and the discharge of moisture is in progress (in most instances) ; but only (c) after the evacuation is over. The reason is that in one case (a) the female has no nourishment, no material, for the dynamis(a) supplied by the male in the semen to draw upon and so to cause the living creature to take shape from it; in the other case (b) it is washed right away owing to the volume of the menstrual fluid. When, however, (c) the discharge is over and most of it has passed off then what remains begins to take shape as a fetus. There are instances of women who conceive without the occurrence of menstrual discharge ; others conceive during its occurrence but not after it. The reasons are these. The former produce only just so much liquid as remains in fertile individuals (b) after the evacuation is over, and there is no surplus residue to be discharged externally ; in the latter, the mouth of the uterus closes up after the evacuation is over. Therefore, when there has been a plentiful discharge and yet the evacuation still continues, though not so copiously that the discharge of moisture carries the semen away with it, that is the time when if they have intercourse women can conceive again. There is nothing odd about the menstrual fluid's continuing to flow after conception has taken place ; indeed it actually recurs afterwards up to a point, but it is scanty and does not last throughout gestation. How-


ever, this is a morbid condition, and that is why it only occurs infrequently and in few subjects. It is what occurs generally that is most in accord with the course of Nature.

By now it is plain that the contribution which the ·female makes to generation is the matter used therein, that this is to be found in the substance constituting the menstrual fluid,(a) and finally that the menstrual fluid is a residue.

There are some who think that the female contributes semen (b) during coition because women some times derive pleasure from it comparable to that of the male and also produce a fluid secretion. This fluid, however, is not seminal ; it is peculiar to the part from which it comes in each several individual ; there is a discharge from the uterus, which though it happens in some women does not in others.(c) Speaking generally, this happens in fair-skinned women (d) who are typically feminine, and not in dark women of a masculine appearance. Where it occurs, this discharge is sometimes on quite a different scale from the semen discharged by the male, and greatly exceeds it in bulk. Furthermore, differences of food

his death. We know now that the menstrual bleeding is a phase in the sexual cycle, this phase being usually succeeded by the periodical liberation of the egg from the ovary, and by its attachment (if fertilized) to the wall of the uterus.

(b) The view that the female also contributed semen was apparently adopted by the Epicureans ; see Lucretius div. 1229 semper enim partus duplici de semine constat; cf. 1247, 1257-1258.

(c) This apparently refers to the so-called vaginal discharge, which is a natural secretion (cf. 739 a 37); but the latter part of the paragraph seems to describe leucorrhoea, which is pathological. The two have apparently been confused. (d)

(d) Cf. H.A. 583 a 11.


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