66 THE-STRUCTURE AND LIFE OF BIRDS cuap. 
necessary. Every one is familiar with the toughness 
and solidity of a chicken’s gizzard. When the 
stomach of a Hawk or Cormorant is set beside it, the 
contrast is very striking. 
In some birds, all of them fish-eaters, the stomach 
has a small third compartment posterior to the 
gizzard.. The entrance to it is guarded by a flap of , 
skin or, in the case of the Darter, it is furnished with 
thick thairlike formations:which at the entrance are 
especially long. The purpose both of the flap of skin 
and of the hairlike growths seems to be to shut out 
all food that has not become thoroughly fluid.t 
On leaving the second compartment of the stomach, 
or the third compartment if there is one, the food 
passes into the smaller intestine, where the process of 
digestion is completed. The duodenum, the first part 
of the smaller intestine, is a U-shaped loop, and in it 
lies a great whitish gland called the Pancreas. The 
liver is a much greater gland within the two lobes of 
which lie the hinder part of the proventriculus and the 
fore part of the gizzard. The liver..and the pancreas 
both pour upon the food in the duodenum the juices of 
digestion. The work of the pancreatic juice is, mainly, to 
break up starch and convert it into sugar, since starch 
as long as it remains starch is of no use to the body as 
food, and to emulsify fat, ze. to dissolve it into fine 
globules. The bile—the juice secreted by the liver— 
is slightly alkaline and extremely bitter. It is im- 
possible here to describe its exact working. When the 
bile and the pancreatic juice have together done their 
1 See Bronn’s 7hier-Reich, vol. “ Aves,” p. 609. There Dr. 
Gadow speaks of it as the Pylorus Magen 
