by Aristotle
9 · We find differences in the vivipara also as compared with one another. Some produce their young alive, not only externally, but also internally, as men, [30] horses, dogs, and all those which have hair, and among aquatic animals, dolphins, whales, and such cetacea.
10 · But the selachia and the vipers produce their young alive externally, but first produce eggs internally. The egg is perfect, for so only can an animal be generated from an egg, and nothing comes from an imperfect one. It is because they [35] are of a cold nature, not hot as some assert, that they do not lay their eggs externally.
11 · At least they certainly produce their eggs in a soft envelope, the reason being that they have but little heat and so their nature does not complete the process of drying the egg-shell. Because, then, they are cold they produce soft-shelled eggs, [719a1] and because the eggs are soft they do not produce them externally; for that would have caused their destruction.
When an animal is produced from an egg, the process is for the most part the same as in birds, for the egg descends and the young is hatched from it near the vagina, where the young is produced in those animals which are viviparous from the beginning. Therefore in such animals the uterus is dissimilar to that of both the [5] vivipara and ovipara, because they participate in both classes; for it is at once near the hypozoma and also stretching along downwards in all the selachia. But the facts about this and the other kinds of uterus must be gathered from the Anatomies and [10] from the History.4 Thus, because they are oviparous, laying perfect eggs, they have the uterus placed high, but, as being viviparous, low, participating in both classes.
Animals that are viviparous from the beginning all have it low, nature here having no other business to interfere with her, and their production having no double character. Besides this, it is impossible for animals to be produced alive near the hypozoma, for the foetus must needs be heavy and move, and that region in the [15] mother is vital and would not be able to bear the weight and the movement. Thirdly, parturition would be difficult because of the length of the passage to be traversed; even as it is there is difficulty with women if they draw up the uterus in parturition by yawning or anything of the kind, and even when empty it causes a feeling of [20] suffocation if moved upwards. For if a uterus is to hold a living animal it must be stronger than in ovipara, and therefore in all the vivipara it is fleshy, whereas when the uterus is near the hypozoma it is membranous. And this is clear also in the case of the animals which produce young by the mixed method, for their eggs are high up [25] and sideways, but the living young are produced in the lower part of the uterus.
So much for the reason why differences are found in the uterus of various animals, and generally why it is low in some and high in others near the hypozoma. [30]
12 · Why is the uterus always internal, but the testes sometimes internal, sometimes external? The reason for the uterus always being internal is that in this is contained the offspring which needs guarding, shelter, and concoction, while the outer surface of the body is easily injured and cold. The testes vary in position because they also need shelter and a covering to preserve them and to mature the [719b1] semen; for it would be impossible for them, if chilled and stiffened, to be drawn up and discharge it. Therefore, whenever the testes are visible, they have a cuticular covering known as the scrotum. If the nature of the skin is opposed to this, being too [5] hard to be adapted for enclosing them or for being soft like a true skin,5 as with the scaly integument of fish and reptiles, then the testes must be internal. Therefore they are so in dolphins and all the cetacea which have them, and in the oviparous [10] quadrupeds among the scaly animals. The skin of birds also is hard so that it will not conform to the size of anything and enclose it neatly. (This is another reason with all these animals for their testes being internal besides those previously mentioned as arising necessarily from the details of copulation.) For the same reason they are internal in the elephant and hedgehog, for the skin of these, too, is not well suited to [15] keep the protective part separate.
The position of the uterus differs in animals viviparous within themselves and those externally oviparous, and in the latter class again it differs in those which have [20] the uterus low and those which have it near the hypozoma, as in fishes compared with birds and oviparous quadrupeds. And it is different again in those which produce young in both ways, being oviparous internally and viviparous externally. For those which are viviparous both internally and externally have the uterus placed [25] on the abdomen, as men, cattle, dogs, and the like, since it is expedient for the safety and growth of the foetus that no weight should be upon the uterus.
13 · The passages also are different through which the solid and liquid [30] excreta pass out in all the vivipara. That is why both males and females in this class all have a part whereby the urine is voided, and this serves also for the issue of the semen in males, of the offspring in females. This passage is situated above and in front of the passage of the solid excreta. Those ovipara that produce imperfect eggs; [720a1] e.g. the oviparous fish, have their uterus not under the abdomen but near the loin; for the growth of the egg does not hinder this, since the growing creature is perfected and develops externally.6 The passage is the same as that of the solid [5] nutriment in all those animals that have no penis, in all the ovipara, even those of them that have a bladder, as the tortoises. For it is for the sake of generation, not for the evacuation of the urine, that the passages are double; but because the semen is naturally liquid, the liquid excretion also shares the same passage. This is clear [10] from the fact that all animals produce semen, but all do not void liquid excrement. Now the spermatic passages of the male must be fixed and must not wander, and the same applies to the uterus of the female, and this fixing must take place at either the front or the back of the body. To take the uterus first, it is in the front of the [15] body in vivipara because of the foetus, but at the loin and the back in ovipara. All animals which are internally oviparous and externally viviparous are in an intermediate condition because they participate in both classes, being at once oviparous and viviparous. For the upper part of the uterus, where the eggs are [20] produced, is under the hypozoma by the loin and the back, but as it advances7 is low at the abdomen; for it is in that part that the animal is viviparous. In these also the passage for solid excrement and for copulation is the same, for none of these, as has been said already, has a separate pudendum.
[25] The same applies to the passages in the male, whether they have testes or no, as to the uterus of the ovipara. For in all of them, the ducts adhere to the back and the region of the spine. For they must not wander but be settled, and that is the character of the region of the back, which gives continuity and stability. Now in [30] those which have internal testes, the ducts are fixed from the first, and they are fixed in like manner if the testes are external; then they meet together towards the region of the penis.
The like applies to the ducts in the dolphins, but they have their testes hidden [35] under the abdominal cavity.
We have now discussed the situation of the parts contributing to generation, and the causes thereof. [720b1]
14 · The bloodless animals do not agree either with the sanguinea or with each other in the fashion of the parts contributing to generation. There are four classes still left to deal with, first the crustacea, secondly the cephalopoda, thirdly [5] the insects, and fourthly the testacea. We cannot be certain about all of them, but that most of them do not copulate is plain; in what manner they unite must be stated later.
The crustacea copulate like the retromingent quadrupeds, fitting their tails to [10] one another, the one supine and the other prone. For the fins attached to the sides of the tail being long prevent them from uniting with the belly against the back. The males have fine spermatic ducts, the females a membranous uterus alongside the intestine, cloven on each side, in which the egg is produced. [15]
15 · The cephalopoda entwine together at the mouth, pushing against one another and enfoldin
g their tentacles. This attitude is necessary, because nature has bent backwards the end of the intestine and brought it round near the mouth, as has been said before in the treatise on Parts of Animals8 The female has a part [20] corresponding to the uterus, plainly to be seen in each of these animals, for it contains an egg which is at first indistinct but afterwards splits up into many; each of these eggs is imperfect when deposited, as with the oviparous fishes. In the cephalopoda (as also in the crustacea) the same passage serves to void the [25] excrement and leads to the part like a uterus,† for the male discharges the seminal fluid through this passage. And it is†9 on the lower surface of the body, where the mantle is open and the sea-water enters the cavity. Hence the union of the male with the female takes place at this point, for it is necessary, if the male discharges either [30] semen or a part of himself or any other force, that he should unite with her at the uterine passage. But the insertion, in the case of the octopus, of the tentacle of the male into the funnel of the female, by which tentacle the fishermen say the male copulates with her, is only for the sake of attachment, and it is not an organ useful [35] for generation, for it is outside the passage and indeed outside the body.
Sometimes also cephalopoda unite by the male mounting on the back of the female, but whether for generation or some other cause has not yet been [721a1] observed.
16 · Some insects copulate and the offspring are produced from animals of the same name, just as with the sanguinea; such are the locusts, cicadae, spiders, wasps, and ants. Others unite indeed and generate; but the result is not a creature of [5] the same kind, but only a grub, and these insects do not come into being from animals but from putrefying matter, liquid or solid; such are fleas, flies, and cantharides. Others again are neither produced from animals nor unite with each [10] other; such are gnats, mosquitoes, and many similar kinds. In most of those which unite the female is larger than the male. The males do not appear to have spermatic passages. In most cases the male does not insert any part into the female, but the female from below upwards into the male; this has been observed in many cases (as [15] also that the male mounts the female),10 the opposite in few cases; but observations are not yet comprehensive enough to enable us to make a distinction of classes. And generally it is the rule with most of the oviparous fish and oviparous quadrupeds that the female is larger than the male because this is expedient in view of the [20] increase of bulk in conception by reason of the eggs. In the female the part analogous to the uterus is cleft and extends along the intestine, as with the other animals; in this are produced the results of conception. This is clear in locusts and [25] all other large insects whose nature it is to unite—most insects are too small.
Such is the character of the generative organs in animals which were not spoken of before. It remains now to speak of the homogeneous parts concerned, the seminal fluid and milk. We will take the former first, and treat of milk afterwards.
[30] 17 · Some animals manifestly emit semen, as all the sanguinea, but whether the insects and cephalopoda do so is uncertain. Therefore this is a question to be considered, whether all males do so, or not all; and if not all, why some do and some not; and whether the female also contributes any semen or not; and, if not semen, [721b1] whether she does not contribute anything else either, or whether she contributes something else which is not semen. We must also inquire what those animals which emit semen contribute by means of it to generation, and generally what is the nature [5] of semen, and of the menstrual flow in all animals which discharge this liquid.
Now it is thought that all animals are generated out of semen, and that the semen comes from the parents. That is why it is part of the same inquiry to ask whether both male and female produce it or only one of them, and to ask whether it comes from the whole of the body or not from the whole; for if the latter is true it is [10] reasonable to suppose that it does not come from both parents either. Accordingly, since some say that it comes from the whole of the body, we must investigate this question first.
The proofs from which it can be argued that the semen comes from each and every part of the body11 may be reduced to four. First, the intensity of the pleasure [15] of coition; for the same state of feeling is more pleasant if multiplied, and that which affects all the parts is multiplied as compared with that which affects only one or a few. Secondly, the argument that mutilated parents produce mutilated offspring; for they argue that since the parent is deficient in this part the semen does not come from thence, and the result is that the corresponding part is not formed in the [20] offspring. Thirdly, the resemblances to the parents; for the young are born like them part for part as well as in the whole body; if then the coming of the semen from the whole body is cause of the resemblance of the whole, so the parts would be like because it comes from each of the parts. Fourthly, it would seem to be reasonable to say that as there is some first thing from which the whole arises, so it is also with [25] each of the parts, and therefore if semen is cause of the whole so each of the parts would have a seed peculiar to itself. And these opinions are plausibly supported by such evidence as that children are born with a likeness to their parents, not only in congenital but also in acquired characteristics; for before now, when the parents [30] have had scars, the children have been born with a mark in the form of the scar in the same place, and there was a case at Chalcedon where the father had a brand on his arm and the letter was marked on the child, only confused and not clearly articulated. That is pretty much the evidence on which some believe that the semen comes from all the body.
18 · On examining the question, however, the opposite appears more likely; [722a1] for it is not hard to refute the above arguments and besides the view involves impossibilities. First, then, the resemblance of children to parents is no proof that the semen comes from the whole body, because the resemblance is found also in voice, nails, hair, and way of moving, from which nothing comes. And men generate [5] before they yet have certain characters, such as a beard or grey hair. Further, children are like their more remote ancestors from whom nothing has come; for the resemblances recur at an interval of many generations, as in the case of the woman in Elis who had intercourse with a negro; her daughter was not negroid but the son [10] of that daughter was. The same thing applies also to plants; for it is clear that if this theory was true the seed would come from all parts of plants also; but often a plant does not possess one part, and another part may be removed, and a third grows afterwards. Besides, the seed does not come from the pericarp, and yet this also comes into being with the same form as in the parent plant. [15]
We may also ask whether the semen comes from each of the homogeneous parts only, such as flesh and bone and sinew, or also from the heterogeneous, such as face and hands. For if from the former only, we object that the resemblance exists rather in the latter; if then it is not because of the semen coming from all parts that children resemble their parents in these, what is there to stop the homogeneous [20] parts also from being like for some other reason than this? If the semen comes from the heterogeneous alone, then it does not come from all parts; but it is more fitting that it should come from the homogeneous parts, for they are prior to the heterogeneous which are composed of them; and as children are born like their [25] parents in face and hands, so they are in flesh and nails. If the semen comes from both, what would be the manner of generation? For the heterogeneous parts are composed of the homogeneous, so that to come from the former would be to come from the latter and from their composition. Similarly, take a written name: if anything came from the whole of it, it would be from each of the syllables, and if [30] from these, from the letters and their composition. So that if really flesh and bones are composed of fire and the like elements, the semen would come rather from the elements; for how can it come from their composition? Yet without this composition there would be no resemblance. If again something creates this composition later, it [722b1] would be this that would be the cause of the resemblance, not the coming of the semen from
every part of the body.
Further, if the parts of the future animal are separated in the semen, how do they live? and if they are connected, they would form a small animal.
[5] And what about the generative parts? For that which comes from the male is not similar to what comes from the female.
Again, if the semen comes from all parts of both parents alike, the result is two animals; for the offspring will have all the parts of both. That is why Empedocles seems to say what agrees pretty well with this view (if we are to adopt it), to a [10] certain extent at any rate, but to be wrong if we think otherwise.12 For he declares that there is a sort of tally in the male and female, and that the whole offspring does not come from either, ‘but sundered is the fashion of limbs, some in man’s . . .’13 For why does not the female generate from herself if the semen comes from all parts [15] alike and she has a receptacle? But, it seems, either it does not come from all the parts, or if it does it is in the way Empedocles says, not the same parts coming from each parent, which is why they need intercourse with each other.
Yet this also is impossible, just as much as it is impossible for the parts when full grown to survive and have life in them when torn apart, as Empedocles accounts [20] for the creation of animals in the time of his Reign of Love, saying that ‘many heads sprang up without necks’,14 and later on these isolated parts combined into animals. Now that this is impossible is plain, for neither would the separate parts be able to survive without having any soul or life in them, nor if they were living things, so to say, could several of them combine so as to become one animal again. Yet those who [25] say that semen comes from the whole of the body really have to talk in that way, and as it happened then in the earth during the Reign of Love, so it happens according to them in the body. Now it is impossible that the parts should be united together when they come into being and should come from different parts of the parent, meeting together in one place. Then how can the upper and lower, right and left, front and [30] back parts have been sundered? All these points are unintelligible. Further, some parts are distinguished by possessing a faculty, others by being in certain conditions; the heterogeneous, as tongue and hand, by the faculty of doing something, the homogeneous by hardness and softness and the other similar conditions. Blood, then, will not be blood, nor flesh flesh, in any and every state. It is clear, then, that that which comes from any part, as blood from blood or flesh from [723a1] flesh, will not be synonymous with that part. But if it is something different from which the blood comes, the coming of the semen from all the parts will not be the cause of the resemblance, as is held by the supporters of this theory. For if blood is formed from something which is not blood, it is enough that the semen come from [5] one part only; for why should not all the parts be formed from one part? Indeed, this theory seems to be the same as that of Anaxagoras, that none of the homogeneous parts come into being, except that these theorists assume, in the case of the generation of animals, what he assumed of everything.