44 NUTRITION OF GRAMINIVORA. 



The nutriment of carnivorous animals is derived 

 originally from blood ; in their stomach it becomes dis- 

 solved, and capable of reaching all other parts of the 

 body ; in its passage it is again converted into blood, 

 and from this blood are reproduced all those parts of 

 their organization which have undergone change or 

 metamorphosis. 



With the exception of hoofs, hair, feathers, and the 

 earth of bones, every part of the food of carnivorous 

 animals is capable of assimilation. 



In a chemical sense, therefore, it may be said that a 

 carnivorous animal, in supporting the vital process, con- 

 sumes itself. That which serves for its nutrition is 

 identical with those parts of its organization which are 

 to be renewed. 



The process of nutrition in graminivorous animals 

 appears at first sight altogether different. Their diges- 

 tive organs are less simple, and their food consists of 

 vegetables, the great mass of which contains but little 

 nitrogen. 



From what substances, it may be asked, is the blood 

 formed, by means of which their organs are developed ? 

 This question may be answered with certainty. 



Chemical researches have shown, that all such parts 

 of vegetables as can afford nutriment to animals contain 

 certain constituents which are rich in nitrogen ; and the 

 most ordinary experience proves, that animals require 

 for their support and nutrition less of these parts of 

 plants in proportion as they abound in the nitrogenized 



