50 USES OF THE STARCH. CASEINE. 



The most extensive class of animals, the graminivora, 

 cannot live without these substances ; their food must 

 contain a certain amount of one or more of them, and 

 if these compounds are not supplied, death quickly 

 ensues. 



This important inquiry extends also to the consti- 

 tuents of the food of carnivorous animals in the earliest 

 periods of life ; for this food also contains substances, 

 which are not necessary for their support in the adult 

 state. 



The nutrition of the young of carnivora is obviously 

 accomplished by means similar to those by which the 

 graminivora are nourished ; their development is de- 

 pendent on the supply of a fluid, which the body of the 

 mother secretes in the shape of milk. 



Milk contains only one nitrogenized constituent, known 

 under the name of caseine ; besides this, its chief ingre- 

 dients are butter (fat), and sugar of milk. 



The blood of the young animal, its muscular fibre, 

 cellular tissue, nervous matter, and bones, must have 

 derived their origin from the nitrogenized constituent of 

 milk, the caseine ; for butter and sugar of milk contain 

 no nitrogen. 



Now, the analysis of caseine has led to the result, 

 which, after the details given in the last section, can 

 hardly excite surprise, that this substance also is identi- 

 cal in composition with the chief constituents of blood, 

 fibrine and albumen. Nay, more, a comparison of its 

 properties with those of vegetable caseine has shown 

 that these two substances are identical in all their prop- 



