ABSORPTION 367 



ruminants whole grain is digested as completely as crushed 

 grain. 



(4) Watering. — It is commonly believed that drinking 

 after eating tends to wash the food out of the stomach and 

 decrease the amount digested, and that therefore animals, 

 and especially horses, should be watered before being fed. 

 According to Scheunert, however, water drunk by the horse 

 after feeding, passes between the wall of the stomach and its 

 contents to the duodenum with very little disturbance or 

 dilution of the contents, and experiments by Tangl show 

 that less water is drunk and the food is not so completely 

 digested when watering takes place prior to feeding, and no 

 water is allowed during or after feeding. These results 

 agree with those obtained on both dogs and men. 



Unless there be some good reason supported by experi- 

 mental evidence, the prevention of an animal from drinking 

 either before, during, or after feeding according to its 

 inclination does not seem to be warranted. It should be 

 noted, however, that in watering and feeding any sudden 

 change in a system that the animal has been accustomed to 

 may lead to disturbance of the digestive functions. 



(5) Proportion of Constituents of Food. — Excess of carbo- 

 hydrates in the diet decreases the percentage availability of 

 all the constituents, but especially the apparent availability 

 of the nitrogenous substances. According to Kellner, 

 decreased digestion occurs when the nutritive ratio (p. 368) 

 is wider than 1-8 in ruminants and 1-12 in pigs. 



Armsby suggests that the decrease in the amount 

 digested is caused by a modification of the fermentation 

 processes due to the presence of excessive amounts of soluble 

 carbohydrates which bacteria attack in preference to the 

 crude fibre. The fibre consequently escapes disintegration 

 and carries off the contained digestible constituents. On 

 the addition of protein to the diet the digestibility is 

 increased, the reason assigned being that the increase of 

 nitrogenous material stimulates the multiplication and 

 activity of the bacteria. 



As Kellner has pointed out, the apparent decrease in the 

 percentage of protein digested is not a true decrease. As 



