THE STOMACH. 49 



which it depends chiefly for support, since we have seen that 

 until these grains are bruised and crushed, the gastric juice 

 will not act upon mealy or nourishing matter contained 

 within the husk. And there are reasons for supposing, that 

 in this process, nature acts according to certain wise laws, in 

 most cases suiting the quantity and quality of the gastric 

 juice to the necessities of the hird. One of our ahlest ana- 

 tomists,* indeed, concluded that the stomach hecame more 

 and more fitted to economize the food, as the country to 

 which the bird belongs became less fertile, or less able 

 to provide the requisite supply. In some cases, where the 

 gizzard is imperfect, and is unfitted to act the part of a 

 grinder, the bird is led by instinct to provide itself with a 

 singular substitute. 



We have alluded to the strange matters found in the 

 stomach of the Ostrich which died in this country. Now, the 

 reason why these birds and some others, such as the Emu 

 and Cassowary, which move over the ground by running 

 instead of flying, swallow such strange hard substances, is 

 this: their digestive organs are, generally speaking, weak; 

 accordingly, their well-known propensity for swallowing glass, 

 iron, and other such substances, is an instinctive remedy for 

 this deficiency, which is further assisted by their habits of 

 running ; this motion producing such an increased shaking 

 or rubbing together between these hard substances which 

 they swallow, and their natural food, as to render the strong 

 action of a gizzard in a great degree useless. Those who 

 take an interest in poultry are aware that they are in the 

 constant habit of picking up small stones. Many persons 

 consider this as an accidental occurrence; but it is by no 

 means so : they do it, like the Ostrich, for the purpose of 

 assisting the powers of the gizzard in grinding the shells and 

 outer coats of the grains, so as to render them fit for final 

 digestion. In the stomach of a Turkey-hen, nearly one 

 hundred stones have been counted, and in that of a Goose, a 

 still larger number; but these are nothing to the extra- 



* Sir E. Home. 



