THE STOMACH. 49 



working of this grinding-machine within its body, a fowl, for 

 instance, without a gizzard, would receive no sustenance from 

 the grains on 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 suppos- 

 ing 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 bird. One of our ablest 

 anatomists,* indeed, concluded that the stomach became more 

 and more fitted to economise 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 imper- 

 fect, 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 defi- 

 ciency, w T hich 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 pick- 

 ing up small stones. Many persons consider this 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 



* Sir E. Home. 



D 



