VEGETABLE FOODS. 161 



herbivorous animals are precisely similar to the inorganic constituents 

 of the vegetable matters which serve as their food. The inorganic con- 

 stituents of the blood are the same as the inorganic constituents of 

 tissues. Herbivora and carnivora therefore find in their foods their 

 necessary inorganic tissue-constituents. The statement above made that 

 animals must obtain in their foods constituents of their blood and tissues 

 read}- prepared may be modified in the case of the fats; for it has been 

 found that, so far from being derived from fats taken as food, the greater 

 part of the fats stored up in the body is derived from the breaking up 

 of other organic bodies, especially the albuminoids. 



I. VEGETABLE FOODS. 



The nutritive principles of vegetable foods are disseminated 

 in various proportions in different parts of all vegetables ; there is 

 therefore no vegetable which is intrinsically incapable of serving as 

 animal food. But all vegetables do not contain these nutritive principles 

 in equal degrees, or in such a state as to permit of their isolation 

 and appropriation by the animal digestive apparatus ; nor are they in 

 all the vegetables free from noxious principles. Thus, some vegetables, 

 as the herbaceous plants, contain nutritive principles in all their parts ; 

 others, only in their roots, stem, bark, leaves, fruit, or juices. Some maj- 

 form suitable foods for a large number of different species of animals ; 

 others are only capable of nourishing a single species ; and some plants 

 which are food for certain groups of animals are poisons to others. The 

 parts of plants above the ground — that is, their stem, leaves, flowers, and 

 fruits — are in general the most nutritious from the time when vegetation 

 is well commenced to the time of flowering, because then the nutritive 

 principles are not yet fixed in the organs of fructification, and the parts 

 in which they are disseminated are soft and tender. Earlier than this 

 the herbaceous plants are too watery and later too dry to prove very 

 nutritious. The stems of leguminous plants are nutritive while young, 

 while their leaves are suitable for food in all varieties of vegetation. The 

 roots of plants, when soft and succulent, serve as food for many animals, 

 such as the hog and bear, the tapir and hippopotamus, and when culti- 

 vated form valuable food for man. Soft and pulpy fruits, dried fruits, 

 nuts, hulls, and seeds, which are almost invariably rich in mucilaginous 

 matters, — with sugar, starch, oil, and nitrogenous principles,— are often 

 food for many animals. Under certain circumstances, parts of plants 

 which are usually but slightly nutritive, such as the bark, stems, and 

 roots, or even woody tissue, may serve as foods, especially after having 

 undergone partial decomposition, for many animals, particularly the 

 beaver and other rodents, and various insects. 



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