142 



GROWTH AND FOOD OF ANIMALS. 



and vigor after they have arrived at maturity. The food of 

 animals is digested in the stomach and intestines; by this 

 process, it is converted into chyle, and absorbed by the lacteal 

 vessels in the manner already described. But how this chyle, 

 or nutritious matter, after mingling with the general mass of 

 blood, contributes to the growth and repairs the waste of ani- 

 mal bodies, is a mystery which projiably never will be fully 

 unfolded by human sagacity. 



' Various theories have been invented by different philoso- 

 phers, with a view to the explanation of this mystery; but 

 they have either proved to be entirely without foundation on 

 facts, or to be totally inadequate to account for the phenomena 

 observed. Our knowledge concerning the nature of nutrition 

 and growth, is extremely limited, and must continue to be so. 

 We know that, in the animal kingdom, nutrition is performed 

 by means of the blood, which is forcibly propelled through 

 every part of the body by the action of the heart and arteries ; 

 and that vegetables, in a similar manner, are nourished by 

 the ascension and distribution of the sap. But of the appli- 

 cation of the nutritive particles to the various parts of organ- 

 ized bodies, and of the manner in which they expand the 

 organs, or repair their continual waste and loss of substance, 

 we must content ourselves with remaining in perpetual igno- 

 rance. .It is, however, the opinion of the most rational and 

 well-informed physiologists, that the nutritious particles of 

 food are conveyed by the arteries, and applied by their ex- 

 tremities to the various parts of animal bodies which require 

 to be repaired or expanded.' 



In general, the food of animals, and particularly of the 

 human species, consists of animal and vegetable substances, 

 combined with water, or other fluids. The Gentoo, and some 

 other southern nations, live entirely upon vegetable diet. 

 From the accounts we have of the different regions of the 

 earth, it appears, that the natives of warm climates, where the 

 cultivation of plants is practised, employ a greater proportion 

 of vegetable food than in the more northern countries. The 

 inhabitants of Lapland have little or no dependence on the 

 fruits of the earth. They neither sow nor reap. They still 

 remain, and, from the nature of their climate, must forever 

 remain, in the shepherd state. Their comparative riches con- 

 sist entirely of the number of reindeer possessed by indi- 

 viduals. Their principal nourishment is derived from the 

 flesh and milk of these animals. In autumn, however, they 

 catch great multitudes of fowls, most of them of the game 



