318 PHILOSOPHY OF ZOOLOGY. 



The value of these experiments is reduced almost to no- 

 thing, when we consider, that an animal, naturally carni- 

 vorous, and, in a domestic state, omnivorous, is, all at once, 

 restricted to diet and drink foreign to its nature, and with 

 which it was never accustomed. In such circumstances, 

 we may expect a derangement of the system to take place 

 from a variety of causes. 



In the first experiment, where the dog was fed with 

 white sugar and distilled water, the elementary substances 

 which the system could obtain from these, were oxygen, 

 carbon and hydrogen, together with a little azote, contain- 

 ed in the air within the pores of the sugar, or mixed with 

 both the sugar and distilled water in the process of masti- 

 cation. But we have seen, that in the saliva alone, a fluid 

 essentially necessary to the very commencement of the pro- 

 cess of digestion, phosphorus, muriatic acid, lime and so- 

 da, enter as constituent ingredients. Azote may have been 

 obtained from the air in respiration. We may, therefore, 

 with great propriety, regard the decay and death of the 

 animal, as originating in the want of these other elementary 

 substances, rather than to the azote, the one to which they 

 are referred by the author. If saliva could not be pro- 

 duced from such food, much less could blood, which, in ad- 

 dition to the elementary bodies now mentioned, contains 

 magnesia, potash and iron. It is obvious, therefore, that in 

 these experiments there were too many deranging causes ope- 

 rating, to permit a safe conclusion to be drawn from them. 



In attending to the animal economy, in reference to the 

 digestive system, it is interesting to observe the various 

 means which are employed, in order to bring the food with- 

 in the reach of the organs employed in deglutition. In 

 man, the hand is extensively used for this purpose, and for 

 which it is admirably adapted by the pliability of the fing- 

 ers, and the opposition of the thumb in the act of grasping. 



