254 POULTKY CULTURE 



The crop is a storehouse for the food during the hours of 

 foraging. From here it is forced out as needed by aid of its 

 muscular walls, which forces it into the second portion of the 

 esophagus to the proventriculus or true stomach (d). 



The proventriculus is provided with glands located in its 

 walls which secrete a gastric or stomach juice in which the 

 food soaks before it passes into the gizzard (e). The reaction 

 of the stomach contents is acid; this acidity depends upon 

 hydrochloric and lactic acids secreted by the cells located in 

 the stomach walls. 



Gastric juice is a thin, transparent, watery fluid which is acid 

 in reaction. It contains enzymes and acids. Its chief fer- 

 ment is pepsin. Pepsin, like other ferments, belongs to the 

 proteid group. This ferment in the presence of acids acts 

 upon the protein group of food nutrients. In this action in- 

 soluble proteins are converted into soluble forms for absorp- 

 tion into the blood through the blood capillaries. In this 

 change the protein is converted first into syntonin, then into 

 primary, and next into secondary proteoses, and last into 

 soluble peptones. 



The gizzard is an organ which is to the bird what the molar 

 teeth are to solipeds. It is here by aid of grit and the contrac- 

 tion of its powerful muscular walls that the feed is reduced to 

 fineness so that the digestible nutrients may be digested — that 

 is, rendered into solution and utilized by the body. It will be 

 noted that the opening into the gizzard from the proventriculus 

 is close to the outlet from the gizzard into the small intestines 

 (Fig. 98, letters d, e, and/). 



The Pancreas. — The first portion of the small intestines 

 forms a loop in which lays a whitish-yellow elongated gland, 

 the pancreas (/). The pancreas secretes the pancreatic juice 

 which performs certain important functions in digestion. It 

 is very difficult to obtain pancreatic fluid in a pure state, but 

 it is probable that it has the same function in digestion in the 

 small intestines of the fowl that it has in other gramnivorous 

 animals. The pancreatic fluid is alkaline in reaction, and is a 

 clear, colorless fluid resembling water. It possesses an un- 

 pleasant saltish taste, and has a specific gravity of from 1010 

 to 1030. On analysis it has been found to contain 98.25 per 



