Page:The Works of William Harvey (part 1 of 2).djvu/359

 The delicate embryo, consequently, whilst it is yet in the vermicular state, is nourished with the thinnest and best con- cocted aliment, the colliquament and thinner albumen ; but when it is older it has food supplied to it more in harmony with its age and strength.

Aristotle describes the relative situation of the several parts in the following words : " In the anterior and posterior part, the membrane of the egg lies under the shell, I do not mean the membrane of the shell itself, but one under this, in which there is contained a clear fluid" the colliquament ; " then the chick and the membrane including it, which keeps it distinct from the fluid around it." But here I suspect that there is an error in the text ; for as the author himself indicates the thing, it ought rather to stand thus: "then the chick, enveloped in a membrane, continues or swims in the clear fluid ;" which mem- brane is not exterior to the one that immediately lines the shell, but another lying under this; which, when the first or external albumen is consumed, and the remainder of the thicker albumen is depressed into the sharp end of the egg, of two membranes forms a single tunic that now begins to present itself like the se- cundine called the chorion. And Aristotle says well, " there is a clear fluid contained in it," by which words he does not mean the albumen, but the colliquament derived from the albumen, and in which the embryo swims ; for the albumen that remains subsides into the small end of the egg.

EXERCISE THE TWENTY-SECOND.

The inspection after the fourteenth day.

From the seventh to the fourteenth day everything has grown and become more conspicuous. The heart and all the other viscera have now become concealed within the abdomen of the embryo, and the parts that formerly were seen naked and pro- jecting externally, can now only be perceived when the thorax and abdomen are laid open. The chick too now begins to be covered with feathers, the roots of which are first perceived as