170 REPTILES AND BIRDS. 
The tongue, like the bill, however, is only an accessory to the 
digestive apparatus; for while the beak serves the purpose of pre- 
hension and trituration, the tongue assists in deglutition or swallowing. 
Digestion is so active in some birds, that they get fat in an excessively 
short space of time. The Ortolan Bunting, and some others, are 
fattened for the table in five or six days. In 
the swelling under the throat called the crop 
(a, Fig. 67), or first stomach, which is largely 
developed in some of the granivorous or grain- 
eating birds, the food remains for a time, where 
| it undergoes certain modifications which faci- 
et litate digestion ; thence it passes into the suc- 
centeric ventricle, or second stomach, (4, Fig. 
i 67), there it imbibes the necessary amount of 
By gastric juice; being finally transformed into 
| Sy chyme in the gizzard (c, Fig. 67), or third 
stomach, which is possessed of great muscular 
power, being capable of acting upon the most 
solid bodies, triturating even the flints and 
gravel which the Gallinaceous Birds swallow to 
aid their digestion. 
It is a curious fact that a grain of seed, 
introduced into the stomach, may be digested 
without alteration, and when ejected will 
germinate, if it meets with no obstacle to its 
vegetation. In this manner trees are frequently 
found in regions where their species appear to 
have been previously unknown. 
Chyle, which is a milky fluid formed from 
=o ae ie the junction of chyme and bile, is received by 
z ‘the small intestine, where the bile also flows 
from the liver and the saliva from the pancreas. 
_ ‘The urinary apparatus consists of the kidneys, two in number, 
thick and irregular, and distinct one from the other, abutting on 
the intestine, which terminates in a species of pouch, or cdoaca, 
through which evacuation, alternately of urine, excrement, and eggs, 
takes place. Such is the general internal anatomy of Birds (Fig. 68). 
The senses of touch, of smell, of taste, and hearing are only slightly 
developed in Birds. Some have spoken of great delicacy of scent 
in Birds of Prey, which are observed to assemble in great numbers 
on fields of battle and other places where carcases are exposed. 
But the opinions of naturalists such as Audubon and Leyvaillant 
