64 THE STRUCTURE AND LIFE OF BIRDS chap. 



once watched by an apparently trustworthy observer, 

 at a repast which lasted for an hour and a half. Each 

 time that the bird rose after diving, he saw the flash 

 of a small fish and the jerk of the neck with which it 

 was swallowed. And the total number of fish dis- 

 posed of he estimated at one hundred and eighty. 

 However small they may have been, it must have 

 required a very large gullet to accommodate them. 



The stomach has two compartments, very different 

 in their structure and function. There is the fore part, 

 or Proventriculus, which is highly glandular, and the 

 hinder part, which has no glands, and to which, when 

 it is very muscular, as it is in many birds, the name 

 of gizzard is given. The proventriculus secretes 

 strong acid juices from its glands, and some kinds 

 of food, such as meat, may, certainly in mammals. 

 probably in birds, be partly absorbed here, the 

 peptone, as it is called, that is formed from them, 

 passing into the blood vessels that are separated only 

 by a very thin membrane from the cavity of the 

 stomach. It has been thought that the process is that 

 called Osmosis, which is as easy to illustrate as it is 

 difficult to explain. If a bladder containing peptone 

 be held under water, a large quantity of the peptone 

 will make its way out into the water, while the bladder 

 will be distended by the water which has made its 

 way in. Peptone is quite exceptional among solu- 

 tions of organic matter in the readiness with which it 

 passes through the walls of a bladder. White of egg, 

 for instance, has been tried in the same way, and 

 hardly any of it has escaped. 



The absorption of food into the blood-vessels is a 



