CHAPTER XVI 



OCCURRENCE AND USES OF IMPORTANT 

 CONSTITUENTS IN AGRICULTURAL 

 PLANTS {Continued) 



FATS AND WAXES 



Plant Fats as Food. — In those crops used as food for domestic 

 animals fats do not play so important a part as do either car- 

 bohydrates or proteins. They are present in much smaller 

 amounts, in general, and in the case of herbivorous animals 

 they contribute only a small amount to the total energy value 

 of the food. It will be recalled also that body fat in animals 

 is formed largely from carbohydrate and not from fat food. 

 While this is true of most domestic animals, it is not true of 

 human beings. Some of the plants or plant parts used by 

 man as food contain large amounts of fat or oil, and from such 

 sources a considerable part of the total energy of the body is 

 derived. 



Occurrence. — Fats, mostly as oils, occur usually as a re- 

 serve food in seeds, often largely replacing carbohydrates. They 

 are also found, to some extent, but never in large amounts, 

 in the vegetative organs, as in grasses, etc. 



In seeds, which contain mostly starch, as the cereal grains, 

 the fat is stored immediately around the germ so that when the 

 germ is removed most of the fat goes with it. This is the 

 reason for the high fat content of so-called germ meal. In 

 seeds which are very rich in fat, as in the castor oil bean, cotton- 

 seed, flaxseed, olive, brazil nut, etc., the fat is variously distrib- 

 uted throughout the seed. 



In the case of common crops, whether these are seeds, as the 



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