1 6^ Mr. Home on the Structure of the Stomachs 
purpose, by dissolving its contents sufficiently to prevent the 
necessity of rumination, or the use of a gizzard. The second 
cavity performs the same office as the plicated portion of the 
fourth cavity of the ruminant, and the fourth is that in which 
the chyle is formed. This complex structure of the stomach in 
the whale tribe, although it gives it an appearance of great 
similarity to that of the ruminant, is not at all formed on the same 
principle, since the additional cavities in the ruminant "are to 
prepare the food for the process of digestion ; while in the 
whale tribe no such preparation is required ; but as the fishes 
they feed upon are swallowed whole, and have large sharp 
bones which would injure any surface not defended by cuticle, 
a reservoir became necessary, in which they may be dissolved 
and converted into nourishment, without retarding the diges- 
tion of the soft parts. The very narrow communication between 
the second, third, and fourth cavities, resembles the opening 
between the cardiac and pyloric portion in fishes. 
The stomachs of this tribe of animals are therefore intro- 
duced here, as being next in order with respect to the com- 
plexity of parts, and having by the division of them led me to 
the present investigation, although it is by no means their 
proper place, with respect to their mode of digestion. 
The animals, nearest allied to the ruminants in their mode 
of digestion, are those which, like them, retain a portion of 
food in the cardiac extremity of the stomach, that it may un- 
dergo a change, before it is submitted to the action of the 
solvent liquor ; and when so hard as to render it neces- 
sary, return it again into the mouth, to be masticated a 
second time. 
The hare and rabbit are of this kind ; the cardiac portion 
of the stomach is never completely emptied, and they occa- 
