Page:The Works of William Harvey (part 1 of 2).djvu/295

 in pursuit to gratify it. But I shall have more to say on this subject in my treatise on the Loves, Lusts, and Sexual Acts of Animals. I return to the matter we have in hand.

EXERCISE THE SEVENTH.

Of the abdomen of the common fowl and of other birds.

From the external orifice proceeding through the vulva we come to the uterus of the fowl, in which the egg is perfected, surrounded with the white and covered with its shell. But before speaking of the situation and connections of this part it seems necessary to premise a few words on the particular ana- tomy of the abdomen of birds. For I have observed that the stomach, intestines, and other viscera of the feathered kinds were otherwise placed in the abdomen, and differently consti- tuted, than they are in quadrupeds.

Almost all birds are provided with a double stomach ; one of which is the crop, the other the stomach, properly so called. In the former the food is stored and undergoes preparation, in the latter it is dissolved and converted into chyme. 1 The familiar names of the two stomachs of birds are the crop or craw, and the gizzard. In the crop the entire grain, &c. that is swal- lowed is moistened, macerated, and softened, and then it is sent on to the stomach that it may there be crushed and commi- nuted. For this end almost all the feathered tribes swallow sand, pebbles, and other hard substances, which they preserve in their stomachs, nothing of the sort being found in the crop. Now the stomach in birds consists of two extremely thick and powerful muscles (in the smaller birds they appear both fleshy and tendinous), so placed that, like a pair of millstones con- nected by means of hinges, they may grind and bruise the food; the place of teeth, which birds want, being supplied by the stones which they swallow. In this way is the food reduced and turned into chyme 1 ; and then by compression (just as we

1 [The word in the original is chyle, for which, in accordance with modern views, chyme is substituted. ED.]