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 bird. One of our ablest ana- 
tomists,^ indeed, concluded that the stomach became 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. 
