70 VEGETABLE FEEDEBS. 



same activity. This is well exemplified in the case 

 of pigeons, and also in that of all the finch tribe, 

 which are active birds, and also very vegetable in 

 their feeding. 



If this excess of food were taken into the stomach 

 at once, and that stomach lodged within the cavity of 

 the body, the same inconveniences would arise as if 

 the craw were situated there ; and the stomach itself, 

 as containing a greater quantity at once, would either 

 require to be more powerful, or it would perform the 

 function of digestion less efficiently. But, with the 

 addition of the craw as a reservoir, the gizzard, or 

 muscular stomach, which may be said to perform the 

 operations of both mastication and digestion, can 

 afford to be smaller ; and this, besides making the 

 organ more efficient, with the same exertion of 

 muscular energy, leaves room for the greater length 

 of the intestinal canal, and for the caeca! appendages 

 which are necessary in extracting the chyle from 

 the vegetable aliment. 



Thus we see that, in the structure of the alimentary 

 system in these birds, there is the same evidence of 

 wisdom of purpose, and perfection of execution, as in 

 that of their external organs. These advantages are 

 not confined to the mere convenience of that system 

 in which they are found. The advantage goes to all 

 the habits of the bird. In birds, as well as in mam- 

 malia, the vegetable feeders are the chief prey of the 

 carnivorous ones, and thus they require to be on the 

 alert, and capable of making their escape at all times 

 when their enemies are abroad. But if they took 

 into the true stomach, and had subjected to the 

 process of digestion at once the great quantity of 

 food which is required for their support, they would, 

 as in the case with birds of prey, be incapable of 



