THE FEED PROBLEM 259 



with soda, in which combination they are known as glyco- 

 cholate of soda and taurocholate of soda. 



These salts are alkaUne in reaction and soluble in water. 



During intervals of active duodenal digestion the bile is 

 stored in the gall-bladder and is poured out into the lumen 

 of the duodenal fold diuing active digestion in that part. It 

 is presumed that the acid material coming from the gizzard 

 into the duodenum stimulates the contraction of the bladder 

 walls, forcing its contents into the intestine. 



Bile does not perform a function of digestion, as does the 

 fp.rments of the gastric and pancreatic juices. 



The bile, being alkaUne in reaction, gradually overcomes the 

 acidity of the material poured into it, neutrahzing it. It pre- 

 cipitates the peptones and albuminoses. Bile acids aid in the 

 emulsification of the fats and is active in the presence of pan- 

 creatic juice. It does not, hke the pancreas, spht up fats into 

 fatty acids and glycerin. The bile salts are decomposed in 

 the presence of free fatty acids, their soda set free, and thus 

 soaps are formed. The soap aids in rendering the emulsifying 

 effects of the bile permanent, thus facilitating the absorption 

 of fats. 



That bile facilitates the passage of the digested fats is demon- 

 strated by experiments with animal membrane, the membrane 

 being moistened with bile readily giving passage to emulsified 

 fats. 



In examining the organs of the fowl it will be found that the 

 liver is decidedly the largest gland in the body, and we find its 

 functions are many. The liver manufactures and stores up in 

 the cells a substance known as glycogen, which is an animal 

 starch. While termed animal starch, it differs from vegetable 

 starch in that it is soluble in cold water, whereas vegetable 

 starch is not. It stains reddish brown by iodin, whereas vege- 

 table starch turns blue. 



The carbohydrates of the food (starch and sugars) digested 

 in the intestines is absorbed by capillaries located in the mu- 

 cous lining of the intestine, thence carried by the portal vein 

 to the Hver, where through the activity of the cytoplasm of 

 the liver cells it is converted into and stored up as glycogen. 

 It is now doled out as needed through the nervous influence 



