only bo correctly arrived at after extensive observations on the mode of generation among animals at large. But of this matter I shall have more to say immediately.
Meantime, however, that we may come to the parts subser- vient to generation, as Fabricius says, 1 "let us consider and perpend in what order the organs subserving generation are pro- duced which are formed first, which last. In this investiga- tion two bases are to be laid, one having reference to the cor- poreal, the other to the incorporeal ; that is to say, to nature and the vital principle. The corporeal base," he continues, " I call that which depends on and proceeds from the nature of the body, and of which illustrations are readily supplied from things made by art; as for example, that every building re- quires a foundation upon which it may be established and reared ; from whence walls are raised, by which both floors and ceilings are supported; then are all the supplementary parts added and ornaments appended : and so, in fact, does nature strive in the construction of the animal body ; for first she forms the bones as a foundation, in order that all the parts of the body may grow upon and be appended to and established around them. These are the parts, in other words, that are first formed and solidified ; for as the bones derive their origin from a very soft and membranous substance, and by and by become extremely hard, much time is required to complete the forma- tion of a bone, and it is therefore that they are first produced. Hence Galen did not compare the formation of the animal body to every kind of artificial structure, but particularly to a ship ; for he says, as the commencement and foundation of a ship is the keel, from which the ribs, circularly curved, proceed on either side at moderate distances from each other, like the sticks of a hurdle, in order that the whole fabric of the vessel may after- wards be reared upon the keel as a suitable basis; so in the formation of the animal body does nature, by means of the outstretched spine and the ribs drawn around it, secure a keel and suitable foundation for the entire superstructure, which she then raises and perfects."
But experience teaches us that all this is very different in fact, and that the bones are rather among the last parts to be
1 Op. suj ra cit. p. 43.
