384 The Feeding of Animals 



changed very little other than being softened by the 

 water swallowed with it, the small amount of mucus 

 and the inconsequential amount of saliva. The high 

 temperature doubtless assists this softening effect, and 

 fermentation also progresses rapidly when food is re- 

 tained long in the crop from injury or by overloading 

 with coarse material. 



The divided crop of pigeons secretes, with both 

 sexes, for several days after the young are hatched, 

 A thick milky fluid which serves to feed the 3'oung 

 birds. With other domestic birds the crop serves for 

 little more than a temporary retaining reservoir. 



The stomach, Avhich is a single organ in some birds, 

 is represented by two reservoirs in domestic fowls. 

 The first, through which the food passes after leaving 

 the crop, is the glandular stomach, the succentric ven- 

 tricle or proventriculus, and the second, closely con- 

 nected, is the gizzard or muscular stomach. The first, 

 from its structure, has been considered the true stom- 

 ach, but it is now believed that gastric juice is secreted 

 in the gizzard. The food does not accumulate in the 

 first stomach, but in passing through carries along such 

 juices as are there secreted. 



The gizzard is a powerful grinding apparatus. 

 There is a strong lining which is capable of resisting 

 great pressure and the action of the sharp sand and 

 pebbles. In this organ the grains and seeds, with 

 other materials, are more finely ground than by the 

 mastication of many other animals. 



The intestines are long in domestic fowls. While 

 serving the same purpose as iu mammals and having 



