Page:The Works of William Harvey (part 1 of 2).djvu/331

 Meantime the chalazse or treadles will be seen to decline from either end of the egg towards its sides, this being occa- sioned by that alteration which we have noticed in the relative situations of the two fluids. The treadle from the blunt end descends somewhat ; the one from the sharp end rises in the same proportion: as in a globe whose axis is set obliquely, one pole is as much depressed below the horizon as the other is raised above it.

The vitellus, too, particularly in the situation of the cica- tricula, begins to grow a little more diffluent than it was, and raises its tunica propria, (which we have found in stale eggs before incubation to be somewhat lax and wrinkled,) into a tumour ; and it now appears to have recovered the same colour, consistency, and sweetness of taste that it had in the egg just laid.

Such is the process in the course of the first day that leads to the production of a new being, such the earliest trace of the future chick. Aldrovandus adds : " the albumen suffers no change," which is correct; but when he asserts that " the semen of the cock can be seen in it," he as manifestly errs. Resting on a most insufficient reason, he thought that the chalazse were the semen of the cock, " because," forsooth, " the eggs that are without chalazse are unfruitful." This I can very well believe ; for these were then no proper eggs ; for all eggs, wind eggs as well as those that are prolific, have chalazse. But he, misled perhaps by the country women, who in Italian call the chalazse galladura, fell into the vulgar error. Nor is Hieronymus Fabricius guilty of a less grave mistake when he exhibits the formation of the chick in a series of engravings, and contends that it is produced from the chalazse ; overlooking the fact that the chalazse are present the whole of the time, and unchanged, though they have shifted their places; and that the commence- ment of the chick is to be sought for at a distance from them.