Food. 299 



bone ; and of this important fact, I mean to avail myself fully when 

 I come to discuss the different articles of Horse-diet. Again, the 

 gastric juice is not only not the same in all animals, but it varies in 

 its properties in the same animal, according the circumstances in 

 which the individual is placed. 



To illustrate the first proposition, I need do no more than mention 

 the case of goats, which not only browse with impunity upon hemlock 

 which is a poison to man, but convert it into nourishment. To 

 prove the second, we have only to state the fact that many animals 

 live solely upon vegetable, some entirely upon animal food, and 

 others, again, upon a mixture of both. But, if in the instance of the 

 two first classes, the food which the animal has been uniformly accus- 

 tomed to, whether vegetable or animal, be suddenly w ithdrawn, and 

 other food substituted, the creature not having the power of digest- 

 ing the new kind of diet, languishes and dies. However, new habits 

 may be induced in the animal, and new properties communicated to 

 the gastric juice, provided the change in the food which is natural to 

 it, be brought about by slow and gradual means. Thus, an eagle 

 may be brought to live upon bread, and a lamb upon flesh, but then 

 the stomach in both cases (to borrow once more Mr. Hunter's strong, 

 but applicable idiom) must be properly educated for the purpose; 

 inasmuch as it is necessary that the change in the animal's natural 

 habits and instincts should be slowly effected, by mixing at first a 

 small quantity of the food not natural to the creature, with that 

 which it instinctively feeds upon ; withdrawing the latter by degrees, 

 whilst the former is encreased in the same proportion. 



Such, then, are the amazing properties and powers of the gastric 

 juice; and philosophers, finding that the phenomena of digestion. 



