Such being the state of the question, it is obvious that all controversy about the matter of animals and their nourishment may be settled without difficulty. For as some believe that the semen or matter emitted in intercourse is taken up from every part of the body, so do they derive from this the resemblance of the offspring to the parents. Aristotle has these words: “Against the opinion of the ancients, it may be said that as they avow the semen to be a derivative from all parts else, we believe the semen to be disposed of itself to form every part; and whilst they call it a colliquament, we are rather inclined to regard it as an excrement” (he had, however, said shortly before that he entitled excrement the remains of the nourishment, and colliquament that which is secreted from the growth by a preternatural resolution); “for that which arrives last, and is the excrement of what is final, is in all probability of the same nature; in the same way as painters have very commonly some remains of colours, which are identical with those they have applied upon their canvass; but anything that is consuming and melting away is corrupt and degenerate. Another argument that the seminal fluid is not a colliquament, but an excrement, is this: that animals of larger growth are less prolific, smaller creatures more fruitful. Now there must be a larger quantity of colliquament in larger than in smaller animals, but less excrement; for as there must be a large consumption of nourishment in a large body, so must there be a small production of excrement. Farther, there is no place provided by nature for receiving and storing colliquament; it flows off by the way that is most open to it; but there are receptacles for all the natural excrements—the bowels for the dry excrements, the bladder for the moist; the stomach for matters useful; the genital organs, the uterus, the mammæ for seminal matter—in which several places they collect and run together.” After this he goes on by a variety of arguments to prove that the seminal matter from which the fœtus is formed is the same as that which is prepared for the nutrition of the parts at large. As if, should one require some pigment from a painter, he certainly would not go to scrape off what he had already laid on his canvass, but would supply the demand from his store, or from what he had over from his work, which was still of the same nature as that which he might have taken away from his picture. So and in like manner the excrement of the ultimate nutriment, or the remainder of the gluten and dew, is carried to the genital organs and there deposited; and this view is most accordant with the production of eggs by the hen.
The medical writers, too, who hold all the parts to be originally formed from the spermatic fluid, and consequently speak of these under the name of spermatic parts, say that the semen is formed from the ultimate nourishment, which with Aristotle they believe to be the blood, being produced by the virtue of the genital organs, and constituting the “matter” of the fœtus. Now it is obvious enough that the egg is produced by the mother and her ultimate nutriment, the nutritious dew, to wit. That clear part of the egg, therefore, that primigenial, or rather antegenial colliquament, is more truly to be reputed the semen of the cock, although it is not projected in the act of intercourse, but is prepared before intercourse, or is gathered together after this, as happens in many animals, and as will perhaps be stated more at length by and by, because the geniture of the male, according to Aristotle, coagulates.
When I see, therefore, all the parts formed and increasing from this one moisture, as “matter,” and from a primitive root, and the reasons already given combine in persuading us that this ought to be so, I can scarcely refrain from taunting and pushing to extremity the followers of Empedocles and Hippocrates, who believed all similar bodies to be engendered as mixtures by association of the four contrary elements, and to become corrupted by their disjunction; nor should I less spare Democritus and the Epicurean school that succeeded him, who compose all things of congregations of atoms of diverse figure. Because it was an error of theirs in former times, as it is a vulgar error at the present day, to believe that all similar bodies are engendered from diverse or heterogeneous matters. For on this footing, nothing even to the lynx’s eye would be similar, one, the same, and continuous; the unity would be apparent only, a kind of congeries or heap—a congregation or collection of extremely small bodies; nor would generation differ in any respect from a [mechanical] aggregation and arrangement of particles.
But neither in the production of animals, nor in the generation of any other “similar” body (whether it were of animal parts, or of plants, stones, minerals, &c.), have I ever been able to observe any congregation of such a kind, or any divers miscibles pre-existing for union in the work of reproduction. For neither, in so far at least as I have had power to perceive, or as reason will carry me, have I ever been able to trace any “similar” parts, such as membranes, flesh, fibres, cartilage, bone, &c., produced in such order, or as coexistent, that from these, as the elements of animal bodies, conjoined organs or limbs, and finally, the entire animal, should be compounded. But, as has been already said, the first rudiment of the body is a mere homogeneous and pulpy jelly, not unlike a concrete mass of spermatic fluid; and from this, under the law of generation, altered, and at the same time split or multifariously divided, as by a divine fiat, from an inorganic an organic mass results; this is made bone, this muscle or nerve, this a receptacle for excrementitious matter, &c.; from a similar a dissimilar is produced; out of one thing of the same nature several of diverse and contrary natures; and all this by no transposition or local movement, as a congregation of similar particles, or a separation of heterogeneous particles is effected under the influence of heat, but rather by the segregation of homogeneous than the union of heterogeneous particles.
And I believe that the same thing takes place in all generation, so that similar bodies have no mixed elements prior to themselves, but rather exist before their elements (these, according to Empedocles and Aristotle, being fire, air, earth, and water; according to chemists, salt, sulphur, and mercury; according to Democritus, certain atoms), as being naturally more perfect than these. There are, I say, both mixed and compound bodies prior to any of the so called elements, into which they are resolved, or in which they end. They are resolved, namely, into these elements according to reason rather than in fact. The so-called elements, therefore, are not prior to those things that are engendered, or that originate, but are posterior rather—they are relics or remainders rather than principles. Neither Aristotle himself nor any one else has ever demonstrated the separate existence of the elements in the nature of things, or that they were the principles of “similar” bodies.
The philosopher,[351] indeed, when he proceeds to prove that there are elements, still seems uncertain whether the conclusion ought to be that they exist in esse, or only in posse; he is of opinion that in natural things they are present in power rather than in action; and therefore does he assert, from the division, separation, and solution of things, that there are elements. It is, however, an argument of no great cogency to say that natural bodies are primarily produced, or composed of those things into which they are ultimately resolved; for upon this principle some things would come out composed, of glass, ashes, and smoke, into which we see them finally reduced by fire; and as artificial distillation clearly shows that a great variety of vapours and waters of different species can be drawn from so many different bodies, the number of elements would have to be increased to infinity. Nor has any one among the philosophers said that the bodies which, dissolved by art, are held pure and indivisible in their species, are elements of greater simplicity than the air, water, and earth, which we perceive by our senses, which we are familiar with through our eyes.
Nor, to conclude, do we see aught in the shape of miscible matter naturally engendered from fire; and it is perhaps impossible that it should be so, since fire, like that which is alive, is in a perpetual state of fluxion, and seeks for food by which it may be nourished and kept in being; in conformity with the words of Aristotle,[352] that “Fire is only nourished, and is especially remarkable in this.” But what is nourished cannot itself be mingled with its nutriment. Whence it follows that it is impossible fire should be miscible. For mixture, according to Aristotle, is the union of altered miscibles, in which one thing is not transformed into another, but two things, severally active and passive, into a third thing. Generation, however, especially generation by metamorphosis, is the distribution of one similar thing having undergone change into several others. Nor are mixed similar bodies said to be generated from the elements, but to be constituted by them in some certain way, solvent forces residing in them at the same time.
These considerations, however, properly belong to the section of Physiology, which treats of the elements and temperaments, where it will be our business to speak of them more at large.