by Aristotle
For such a reason also the testacea in the water vary more in form than those on the land. For the nature of liquid is more plastic than that of earth and yet not much less material, and this is especially true of the inhabitants of the sea, for fresh [761b1] water, though sweet and nutritious, is cold and less material. That is why animals having no blood and not of a hot nature are not produced in lakes nor in the fresher among brackish waters, but only exceptionally; but it is in estuaries and at the [5] mouths of rivers that they come into being, as testacea and cephalopoda and crustacea, all these being bloodless and of a cold nature. For they seek at the same time the warmth of the sun and food; now the sea is not only water but much more material than fresh water and hot in its nature; it has a share in all the parts of the [10] universe, water and air and earth, so that it also has a share in all living things which are produced in connexion with each of these elements.14 Plants may be assigned to land, the aquatic animals to water, the land animals to air, but variations of quantity and distance make a great and wonderful difference. The fourth class must [15] not be sought in these regions, though there certainly ought to be some animal corresponding to the element of fire, for this is counted in as the fourth of the elementary bodies. But the form which fire assumes never appears to be peculiar to it, but it always exists in some other of the elements, for that which is ignited appears to be either air or smoke or earth. Such a kind of animal must be sought in [20] the moon, for this appears to participate in the element removed in the third degree from earth. The discussion of these things, however, belongs to another subject.
To return to testacea, some of them are formed spontaneously, some emit a sort of generative substance from themselves, but these also often come into being [25] from a spontaneous formation. To understand this we must grasp the different methods of generation in plants; some of these are produced from seed, some from slips, planted out, some by budding off alongside, as the class of onions. In the last way are produced mussels, for smaller ones are always growing off alongside the [30] original, but the trumpet-shells, the purple-fish, and those which are said to ‘honeycomb’ emit masses of a liquid slime as if originated by something of a seminal nature. We must not, however, consider that anything of the sort is real semen, but that these creatures participate in the resemblance to plants in the manner stated above. Hence when once one such creature has been produced, then is produced a number of them. For all these creatures are liable to be even spontaneously [762a1] generated, and so to be formed still more plentifully in proportion if some are already existing. For it is natural that each should have some superfluous residue attached to it from the original, and from this buds off each of the creatures growing alongside of it. Again, since the nutriment and its residue possess a like power, it is [5] likely that the product of those testacea which ‘honeycomb’ should resemble the original formation, and so it is natural that a new animal of the same kind should come into being from this also.
All those which do not bud off or ‘honeycomb’ are spontaneously generated. Now all things formed in this way, whether in earth or water, manifestly come into [10] being in connexion with putrefaction and an admixture of rain-water. For as the sweet is separated off into the matter which is forming, the residue of the mixture takes such a form. Nothing comes into being by putrefying, but by concocting; putrefaction and the thing putrefied is only a residue of that which is concocted. For [15] nothing comes into being out of the whole of anything, any more than in the products of art; if it did art would have nothing to do, but as it is in the one case art removes the useless material, in the other nature does so. Animals and plants come into being in earth and in liquid because there is water in earth, and air in water, [20] and in all air is vital heat, so that in a sense all things are full of soul. Therefore living things form quickly whenever this air and vital heat are enclosed in anything. When they are so enclosed, the corporeal liquids being heated, there arises as it [25] were a frothy bubble. Whether what is forming is to be more or less honourable in kind depends on the embracing of the vital principle; this again depends on the medium in which the generation takes place and the material which is included. Now in the sea the earthy matter is present in large quantities, and consequently the testaceous animals are formed from a concretion of this kind, the earthy matter [30] hardening round them and solidifying in the same manner as bones and horns (for these cannot be melted by fire), and the body which contains the life being included within it.
The class of snails is the only class of such creatures that has been seen uniting, but it has never yet been sufficiently observed whether their generation is the result of the union or not.
It may be asked, if we wish to follow the right line of investigation, what it is in [762b1] such animals the formation of which corresponds to the material principle. For in the females this is a residual secretion of the animal, potentially such as that from which it came, by imparting motion to which the principle derived from the male perfects the animal. But here what must be said to correspond to this, and whence [5] comes or what is the moving principle which corresponds to the male? We must understand that even in animals which generate it is from the incoming nourishment that the heat in the animal makes the residue, the beginning of the conception, by secretion and concoction. The like is the case also in plants, except that in these [10] (and also in some animals) there is no further need of the male principle, because they have it mingled with the female principle within themselves, whereas the residual secretion in most animals does need it. The nourishment again of some is earth and water, of others a combination of these, so that what the heat in animals produces from their nutriment, the heat of the warm season in the environment puts [15] together and combines by concoction out of the sea-water and the earth. And the portion of the vital principle which is either included along with it or separated off in the air makes an embryo and puts motion into it. Now in plants which are spontaneously generated the method of formation is uniform; they arise from a part [20] of something, and while some of it is the starting-point of the plant, some is the first nourishment of the young shoots. Other animals are produced in the form of a grub, not only those bloodless animals which are not generated from parents but even some sanguinea, as a kind of mullet and some other river fishes and also the eel kind. [25] For all of these, though they have but little blood by nature, are nevertheless sanguinea, and have a heart with blood in it as the origin of the parts; and the so-called ‘entrails of earth’, in which comes into being the body of the eel, have the nature of a grub.
Hence one might suppose, in connexion with the origin of men and quadrupeds, [30] that, if ever they were really ‘earth-born’ as some say, they came into being in one of two ways; that either it was by the formation of a grub at first or else it was out of eggs. For either they must have had in themselves the nutriment for growth (and such a conception is a grub) or they must have got it from elsewhere, and that either from the mother or from part of the conception. If then the former is impossible (I mean that nourishment should flow to them from the earth as it does in animals from the mother), then they must have got it from some part of the conception, and [763a1] such generation we say is from an egg.
It is plain then that, if there really was any such beginning of the generation of all animals, it is reasonable to suppose it to have been one of these two. But it is less reasonable to suppose that it was from eggs, for we do not see such generation [5] occurring with any animal, but we do see the other both in the sanguinea above mentioned and in the bloodless animals. Such are some of the insects and such are the testacea which we are discussing; for they do not develop out of a part of something (as do animals from eggs), and they grow like a grub. For the grub grows [10] towards the upper part and the first principle, since in the lower part is the nourishment for the upper. And this resembles the development of animals from eggs, except that these latter consume the whole egg, whereas in the grub, when the upper part has grown b
y taking up into itself part of the substance in the lower part, the lower part is then differentiated out of the rest. The reason is that in later life [15] also the nourishment is absorbed by all animals in the part below the hypozoma.
That the grub grows in this way is plain in the case of bees and the like, for at first the lower part is large in them and the upper is smaller. The details of growth in the testacea are similar. This is plain in the whorls of the spiral-shelled creatures, [20] for always as the animal grows the whorls become larger towards the front and what is called the head of the creature.
We have now pretty well described the manner of the development of these and the other spontaneously generated animals. That all the testacea are formed [25] spontaneously is clear from such facts as these. They come into being on the side of boats when the frothy mud putrefies. In many places where previously nothing of the kind existed, the so-called lagoon-oysters, a kind of testacea, have come into [30] being when the spot turned muddy through want of water; thus when a naval armament cast anchor at Rhodes a number of clay vessels were thrown out into the sea, and after some time, when mud had collected round them, oysters used to be found in them. Here is another proof that such animals do not emit any generative substance from themselves; when certain Chians carried some live oysters over from [763b1] Pyrrha in Lesbos and placed them in narrow straits of the sea where tides clash, they became no more numerous as time passed, but increased greatly in size. The so-called eggs contribute nothing to generation but are only a sign of good [5] condition, like fat in the sanguinea, and therefore the oysters are savoury eating at these periods. A proof that this substance is not really eggs is the fact that such ‘eggs’ are always found in some testacea, as in pinnae, trumpet-shells, and purple-fish; only they are sometimes larger and sometimes smaller; in others, as scallops, mussels, and the so-called lagoon-oysters, they are not always present but [10] only in the spring; as the season advances they dwindle and at last disappear altogether; the reason being that the spring is favourable to their being in good condition. In others again, as the ascidians, nothing of the sort is visible. (The details concerning these last, and the places in which they come into being, must be [15] learnt from the History.)
BOOK IV
[20] 1 · We have thus spoken of the generation of animals both generally and separately in all the different classes. But, since male and female are distinct in the most perfect of them, and since we say that the sexes are first principles of all living things whether animals or plants, only in some of them the sexes are separated and [25] in others not, therefore we must speak first of the origin of the sexes in the latter. For while the animal is still imperfect in its kind the distinction is already made between male and female.
It is disputed, however, whether the embryo is male or female, as the case may be, even before the distinction is plain to our senses, and further whether it is thus [30] differentiated within the mother or even earlier. It is said by some, as by Anaxagoras and other of the physicists, that this antithesis exists from the beginning in the seeds; for the seed, they say, comes from the male while the female [764a1] only provides the place, and the male is from the right, the female from the left, and so also that the male embryo is in the right of the uterus, the female in the left. Others, as Empedocles, say that the differentiation takes place in the uterus; for he says that if the uterus is hot what enters it becomes male, if cold, female, the cause [5] of the heat or cold being the flow of the menstrual fluids, according as it is colder or hotter, older or more recent. Democritus of Abdera also says that the differentiation of sex takes place within the mother; that however it is not because of heat and cold that one embryo becomes female and another male, but that it depends on the [10] question which parent it is whose semen prevails,—not the whole of the semen, but that which has come from the part by which male and female differ from one another. This is a better theory, for certainly Empedocles has made a rather lighthearted assumption in thinking that the difference between them is due only to cold and heat, when he saw that there was a great difference in the whole of the [15] sexual parts, the difference in fact between the male pudenda and the uterus. For suppose two animals already moulded in embryo, the one having all the parts of the female, the other those of the male; suppose them then to be put into the uterus as into an oven, the former when the oven is hot, the latter when it is cold; then on the view of Empedocles that which has no uterus will be female and that which has will [20] be male. But this is impossible. Thus the theory of Democritus would be the better of the two, at least as far as this goes, for he seeks for the difference in this development and tries to set it forth; whether he does so well or not is another question.
Again, if heat and cold were the cause of the difference of the parts, this ought to have been stated by those who maintain the view of Empedocles; for to explain [25] the origin of male and female is practically the same thing as to explain this, which is the manifest difference between them. And it is no small matter, starting from temperature as a principle, to collect the cause of the origin of these parts, as if it were a necessary consequence for this part which they call the uterus to be formed [30] in the embryo under the influence of cold but not under that of heat. The same applies also to the parts which serve for intercourse, since these also differ in the way stated previously.
Moreover male and female twins are often found together in the same part of the uterus; this we have observed sufficiently by dissection in all the vivipara, both [35] land animals and fish. Now if Empedocles had not seen this it was only natural for him to fall into error in assigning this cause of his; but if he had seen it it is strange [764b1] that he should still think the heat or cold of the uterus to be the cause, since on his theory both these twins would have become either male or female, but as it is we do not see this to be the fact.
Again he says that the parts of the embryo are sundered, some being in the male and some in the female parent, which is why they desire intercourse with one [5] another. If so it is necessary that the substance of these parts too should be separated from one another and that a union should take place—but not on account of cooling or heating. But perhaps it would be superfluous to discuss thoroughly such a cause1 as this for its whole character seems to be fanciful. If, however, the [10] facts about semen are such as we have actually stated, if it does not come from the whole of the body of the male parent and if the secretion of the male does not give any material at all to the embryo, then we must make a stand against both Empedocles and Democritus and any one else who argues on the same lines. For then it is not possible that the body of the seed should exist sundered, part in the [15] female parent and part in the male, as Empedocles says in the words: ‘But the nature of the limbs hath been sundered, part in the man’s . . . ’;2 nor yet that the whole is drawn off from each parent and the combination of the two becomes male or female according as one part prevails over another. [20]
And, to take a more general view, though it is better to say that the one part makes it female by prevailing through some superiority than to assign nothing but heat as the cause without any reflection, yet, as the form of the pudendum also differs, we need an explanation of the fact that both these parts go along with each other. If it is because they are near each other, then each of the other parts also [25] ought to go with them, for one of the prevailing parts is always near another; thus the offspring would be not only female or male but also like its mother or father respectively.
Besides, it is absurd to suppose that these parts should come into being as something isolated, without the body as a whole having changed along with them. Take first and foremost the blood-vessels, round which the whole mass of the flesh lies as round a frame-work. It is not reasonable that these should become of a [30] certain quality because of the uterus, but rather that the uterus should do so on account of them. For though it is true that each is a receptacle of blood of some kind, still the system of the vessels is prior to the other; the
moving principle must always be prior to that which it moves, and it is because it is itself of a certain [35] quality that it is the cause of the development. The difference, then, of these parts as compared with each other in the two sexes is a result; not this but something else must be held to be the first principle and the cause, even if no semen is secreted by [765a1] either male or female, but the embryo is formed in any way you please.
The same argument as that with which we meet Empedocles and Democritus [5] will serve against those who say that the male comes from the right and the female from the left. If the male contributes no material, there can be nothing in this view. If, as they say, he does contribute something of the sort, we must confront them in the same way as we did the theory of Empedocles, which accounts for the difference [10] between male and female by the heat and cold of the uterus. They make the same mistake as he does, when they account for the difference by their ‘right and left’, though they see that the sexes differ actually by the whole of the sexual parts; for what reason then is the body of the uterus to exist in those embryos which come [15] from the left and not in those from the right? For if an embryo has come from the left but has not acquired this part, it will be a female without a uterus—or maybe a male with one. Besides, as has been said before, a female embryo has been observed in the right part of the uterus, a male in the left, or again both at once in the same [20] part, and this not only once but several times. [Or the male in the right part, the female in the left; and no less both are formed in the right part.]3
Some again, persuaded of the truth of a view resembling that of these philosophers, say that if a man copulates with the right or left testis tied up the [25] result is male or female offspring respectively; so at least Leophanes asserted. And some say that the same happens in the case of those who have one or other testis excised, not speaking truth but vaticinating what will happen from probabilities and jumping at the conclusion that it is so before seeing that it proves to be so. Moreover, they know not that these parts of animals contribute nothing to the [30] production of one sex rather than the other; a proof of this is that many animals in which the distinction of sex exists, and which produce both male and female offspring, nevertheless have no testes, as the footless animals; I mean the classes of fish and of serpents.