116 OUn DOMESTIC FOWLS. 



tliiclcened, like what happens to the udder of 

 females of the class mammalia, during the term 

 of gestation. On comparing the state of the 

 crop when the bird is not sitting with its ap- 

 pearance during incubation, the difference is 

 remarkable. In the first case it is thin and 

 membraneous, but by the time the young are 

 about to be hatched, the whole, except what 

 lies on the windpipe, becomes thickened and 

 takes a glandular appearance, having its in- 

 ternal surface very irregular. It is likewise 

 more vascular than in its former state, that it 

 may convey a quantity of blood sufficient for 

 the secretion of this substance, wiiicli is to 

 nourish the young brood for some days after 

 they are hatched. Whatever may be the con- 

 sistence of this substance when just secreted, 

 it most probably soon coagulates into a granu- 

 lated white curd ; for in such a form I have 

 found it in the crop, and if an old pigeon is 

 killed just as the young ones are hatching, the 

 crop will be found as above described, and in 

 its cavity pieces of curd mixed with some of 

 the common food of the pigeon, such as barley, 

 beans, etc. If we allow either of the parents 

 to feed the young, its crop when examined, 

 will be discovered to contain the same curdled 



