66 THE STRUCTURE AND LIFE OF BIRDS chap. 



necessary. Even- 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 hairlike 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. 1 



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, i.e. 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 Thier-Reich^ vol. " Aves," p. 609. There Dr. 

 Gadow speaks of it as the Pylorus Magen 



