468 GRASSES OF IOWA. 



III. Steapsin, a fat-decomposing ferment, changes fats into 

 glycerin and fatty acids. 



The bile also aids in the preparation of the fats fo" digestion. 



The food, after being prepared by the action of ferments, is 

 absorbed by certain vessels in the intestines, and ultimately 

 becomes a part of the animal body. 



In the process of digestion it has been seen that nature pro- 

 vides for the preparation of two classes of substances that are 

 needed for repairing the waste of the animal body. These two 

 classes are (1) those substances containing nitrogen, or flesh- 

 producing substances, and (2) the carbohydrates, or heat pro- 

 ducing substances. If nature, then, requires that the animal 

 be furnished with these two classes of foods ia order that the 

 body may continue in health, it would be naturally expected 

 that these substances should be furnished in an intelligent 

 manner and meet the demands made by nature upon the ani- 

 mal. The feeding to an animal of a substance con aining an 

 excessive amount of carbohydrates will probably lead to the 

 injury of the organs by overwork, which nature has designed 

 to govern and keep the animal machine in a healthy condi- 

 tion. The use of foods containing a much larger quantity of 

 protein will probably result in the injury to the organs that 

 control other parts of the animal machine. 



It may be of interest to note that the food material as it is 

 absorbed by the vessels of the intestines passes into the b'ood 

 and is carried to the liver. The liver is one of the most 

 impDitant organs that care for the healthy condition of the 

 body. Should the blood containing the digested food material 

 contain an excessive amount of carbohydrates, the liver stores 

 up these substances for some future time when the body will 

 need them, and then they are given up again to the blood, so 

 that the body may continue to be nourished. In a second 

 capacity the liver acts as the control organ in preventing any 

 poisonous products, which may be formed during any fermen- 

 tation process that may have taken place in the digestive tract, 

 from entering the circulating blood system and thus causing 

 abnormal conditions. If these poisonous substances should 

 pass through the vessels of the intestines they are separated 

 and returned again to the intestines to be thrown off from the 

 body as other impurities. The kidneys are also of great value 

 in the serse that they keep the blood in a pure condition in 

 their action of separating the impure substances that have 



