58 
THE STOMACH. 
In considering the real stomach, or gizzard, by 
which name it will be more familiarly known, we 
shall find additional cause for admiration, in the 
mode by which Providence, with reference to the food 
introduced, so nicely balances the grinding powers 
of the gizzard with the dissolving or melting powers 
of the gastric juice. This third or real stomach 
differs, like the gullet, crop, and second stomach, 
very materially in different birds ; hut, generally 
speaking, the action of this gizzard may be com- 
pared to that of a coffee-mill, grinding down the 
various substances introduced, into a pulpy matter. 
In those which feed on flesh and insects, substances 
of no very hard texture, this stomach appears as a 
thin membranous hag, in comparison with the thick 
muscular globes or gizzards of the grain-devouring 
class ; and the reason is evident; for the animal 
matter on which they feed requires no actual 
grinding to reduce it, the action of the gastric juice 
being sufficient for the purpose of dissolving it ; 
whereas, without the powerful 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 sup- 
port, since we have seen that until these grains are 
bruised and crushed, the gastric juice will not act 
upon the mealy or nourishing matter contained 
wdthin the husk. And there are reasons for sup- 
posing, 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, 
* Sir E. Home. 
