ON
ANIMAL GENERATION.
EXERCISE THE FIRST.
Wherefore we begin with the history of the hen's egg.
Hieronymus Fabricius of Aquapendente, (whom, as I have said, I have chosen my informant of the way I am to follow,) in the beginning of his book on the Formation of the Ovum and Chick, has these words: "My purpose is to treat of the formation of the fœtus in every animal, setting out from that which proceeds from the egg: for this ought to take precedence of all discussion of the subject, both because from this it is not difficult to make out Aristotle's views of the matter, and because his treatise on the Formation of the Fœtus from the egg, is by far the fullest, and the subject is by much the most extensive and difficult."
We, however, commence with the history of the hen's egg as well for the reasons above assigned, as because we can thence obtain certain data which, as more familiar to us, will serve to throw light on the generation of other animals; for as eggs cost little, and are always to be had, we have an opportunity from them of observing the first clear and unquestionable commencements of generation, how nature proceeds in the process, and with what admirable foresight she governs every part of the work.
Fabricius proceeds: "Now that the contemplation of the formation of the chick from the egg is of very ample scope, appears from this, that the greater number of animals are pro-
