29 



Table showing the percentage of moisture ; of albuminous and glutinous 

 compounds ; of starsh. gum, sugar and woody fibre ; and of ash and 

 nitrogen, and the equivalent in ammonia contained in the different pro- 

 ducts. It also shows their relative value as food : 



Plants by their vital force assimilate the elements of both 

 the soil and atmosphere, and turn these elements into food for 

 herbiverous animals, which in turn also serve for food for the 

 carnivorous animals and man, thus to borrow a simile, if we 

 take a field and plant grass, and put a dog thereon he will 

 starve, put a sheep, and the sheep will eat the grass, and then 

 serve as food for the dog. 



The organic portions of plants are, as we have said, derived 

 from the atmosphere, and are built up into 



1st. Albumen and gluten, which contain nitrogen, and whose 

 percentage in any grain is the test of its food value. 



2d. Starch, sugar, gum, and oil, which are rich in carbon, and 

 whose functions are chiefly to make fat, and so to sustain the 

 necessary heat of animals. This oil, or fatty matter, renders 

 the grains in which they are found more easy of digestion, as 

 in corn and the yolk of an egg. 



Carniverous animals are nearly destitute of fat, and should 

 an animal be debarred from exercise, and fed on grain rich in 

 carbon as corn, it rapidly increases in fat, as the carbon is not 

 burnt out by the lungs, but is deposited in the tissures. 



