94 ANIMAL FUNCTIONS. 



to treat of the animal functions, reserving for future con- 

 sideration the action of the human muscles, which can 

 be most properly noticed when we come to speak of 

 physical education. 



SOURCES OF NUTRITION. 



265. The nutrition which nature has provided for the 

 various tribes of animals, is derived, entirely, from two 

 sources, namely, from the animal and vegetable king- 

 doms. But as the carnivorous tribes derive their food 

 from those which are herbivorous, the nourishment of all 

 is ultimately derived from the earth itself. 



266. Vegetable Food. The economy of nature is no- 

 where more wonderfully manifest than in the adaptation 

 of animals to the consumption of every kind of nutrition, 

 there being hardly any organized substance which does 

 not furnish food for some living creat* ire. The succu- 

 lent parts of vegetables are not only the chief source of 

 nourishment of the greater proportion of the larger ani- 

 mals, but also serve the same purpose to myriads of 

 insects. Many tribes of birds, likewise, live on vegeta- 

 bles, but insects become the food of the larger number, 

 while riot a few are strictly carnivorous. But while 

 these substances are the common food of the most 

 numerous races, even the hardest parts of vegetables, 

 and the most poisonous plants serve the same purpose 

 to certain other tribes. The larvse of various insects 

 live by eating their way through the diseased portions of 

 timber logs ; while the nettle, the deadly night-shade, the 

 henbane, and other acrid and poisonous plants, afford 

 w T holesome food to several species. Some live on fruits 

 and seeds, and others on the juices which they pump from 

 succulent plants. 



267. Minimal Food. But while a vast number of tribes 

 thus subsist on the fruits of the ground, these in their 

 turn "become the prey of at least as great a number of 



Whence do animals derive their nutrition ? What is said of the ex- 

 tent to which vegetables serve as the food of animals? 



