THE ALIMENTARY CANAL. 73 
head of its victim with its sharp recurving teeth, and 
crushes the body with its overlapping coils. Then, slow- 
ly uncoiling, and covering the carcass with a slimy mucus, 
it thrusts the head into its mouth by main force, the mouth 
stretching marvelously, the skull being loosely put to- 
gether. One jaw is then unfixed, and the teeth withdrawn 
by being pushed forward, when they are again fastened 
farther back upon the animal. The other jaw is then pro- 
truded and refastened ; and thus, by successive movements, : 
the prey is slowly and spirally drawn into the wide gullet. 
CHAPTER, xe 
THE ALIMENTARY CANAL. 
‘The Alimentary Canal is the great route by which nu- 
tritive matter reaches the interior of the body. It is the 
most universal organ in the animal kingdom, and the rest 
are secondary or subservient to it. In the higher animals, 
it consists of a mouth, pharynx, gullet, stomach, and in- 
testine. 
It is a general law, that food can be introduced into 
the living system only in a fluid state. While plants send 
forth their roots to seek nourishment from without, aui- 
mals, which may be likened to plants turned outside in, 
have their roots (called absorbents) directed inward along 
the walls of a central tube or cavity. This cavity is for 
the reception and preparation of the food, so that animals 
may be said to carry their soil about with them. The ne- 
cessity for such a cavity arises not only from the fact that 
the food, which is usually solid, must be dissolved, so as to 
make its way through the delicate walls of the cavity into 
the system, but also from the occurrence of intervals be- 
