which supplies both matter and form to the being engendered ; so in like manner in the generation of the most perfect animals where principles are distinguished, and the seminal elements of animated beings are divided, a new creation is not effected save by the concurrence of male and female, or by two neces- sary instruments. Our hen's egg is of this kind; to its pro- duction in the perfect state the cock and the hen are necessary. The hen engenders in herself, and therefore does she supply place and matter, nutriment and warmth ; but the cock confers fecundity; for the male, as Aristotle says, 1 always perfects ge- neration, secures the presence of a sensitive vital principle, and from such an egg an animal is engendered.
To the cock, therefore, as well as to the hen, are given the organs requisite to the function with which he is intrusted ; in the hen all the genital parts are adapted to receive and contain, as in the cock they are calculated to give and immit, or prepare that which transfers fecundity to the female, ne engendering, as it were, in another, not in himself.
When we anatomize the organs appropriated to generation, therefore, we readily distinguish what each sex contributes in the process ; for a knowledge of the instruments here leads us by a direct path to a knowledge of their functions.
EXERCISE THE THIRTY-NINTH.
Of the cock and the particulars most remarkable in his constitution.
The cock, as stated, is the prime efficient of the perfect or fruitful hen's egg, and the chief cause of generation : without the male no chick would ever be produced from an egg, and in many ovipara not even would any egg be produced. It is, therefore, imperative on us that we look narrowly into his offices and uses, and inquire particularly what he contributes to the egg and chick, both in the act of intercourse and at other times.
1 Op. cit.
