THE NUTRIENTS AND DIGESTION 319 



These are usually four to six inches in length, and more or 

 less completely filled with fecal matter. Their function, if 

 other than absorption, is not understood. 



Rectum. — The rectum terminates the digestive canal, 

 being a short and somewhat enlarged continuation of the 

 intestine.. It is terminated by the cloaca, a chamber common 

 to the digestive and genito-urinary passages, and which 

 opens externally at the anus. One marked function of the 

 rectum is the absorption of watejr from the urine, as it is 

 delivered from the kidneys by the ureters. The urine appears 

 with the feces normally as a white paste. It leaves the 

 kidneys in a highly liquid state. The only possible conclusion 

 from this and other evidence seems to be that the water is 

 reabsorbed by the rectum, to be used further in the economy 

 of the body, travelling as it were in a sort of vicious circle. 

 Weiner, as quoted by Sharpe,^ noted that when an arti- 

 ficial anus was provided so that there was no chance for 

 water to be absorbed by the rectum, hens drank abnormally 

 large amounts of water. 



Bacteria and Digestion. — It is probable that bacterial 

 action is responsible for a part of the digestive process, though 

 studies of the bacterial flora of the digestive tract have not 

 proceeded far enough to give a great deal of accurate infor- 

 mation on the subject. While there is no opportunity for 

 microorganisms to break down crude fiber and make it 

 available, as is done in the rumen (paunch) of the ruminants, 

 the work of Schottelius (as reported by H. J. Wheeler^) 

 seems to show that they enter very markedly into the 

 digestive processes. He hatched chickens from eggs which 

 were free from foreign organisms, in germ-free air, and fed 

 them on sterilized food, only to have them die in two to three 

 weeks. If hatched in the same manner and fed unsterilized 

 or normal food the chickens lived. Other chickens fed like the 

 first until near death were saved by feeding normal chicken 

 feces or unsterilized feed. 



Disposition. — In comparing fowls with other farm animals, 

 besides the anatomical differences, there is a decided difference 



' Sharpe, American Journal of Physiology, vol. xxxi, No. 11. 

 2 Rhode Island Bulletin No. 84. 



