RUMINATION AND EEGUEGITATION. 293 



The ordinary food taken by these animals passes, in greatest 

 part, into the first stomach or rumen ; a small portion, which 

 consists of the moist and finely divided parts, passes into the 

 second stomach, but none is received into the third and 

 the fourth stomach. 1 In the first stomach, are thus collected 

 all the dry and coarse parts of the food, which are here 

 slowly but continuously agitated by the movements of the 

 muscular coat Most of the liquids taken and a consider- 

 able quantity of saliva accumulate in the second stomach, or 

 reticulum. When the proper quantity of food has been taken, 

 small quantities are forced by the contractions of the muscu- 

 lar wall into a canal or groove, which is a continuation of the 

 oesophagus, and is bounded by two lips capable of closing over 

 the top, so as to completely separate it from the great cavity. 

 Here the food is moistened by fluids poured in from the sec- 

 ond stomach, and a small bolus, moulded by the muscular 

 contractions of the walls of the canal, is prepared to be passed 

 back to the mouth. The bolus is then passed along the 

 oesophagus by the anti-peristaltic contractions of its muscular 



1 All ruminating animals have multiple stomachs, generally with four dis- 

 tinct divisions. The first stomach, called the rumen or paunch, is the most 

 capacious. It is generally divided into several sacs, and is lined by a mucous 

 membrane with numerous villi, and covered by a dense layer of epithelium. 

 The second stomach, called the reticulum, is very much smaller than the first. It 

 presents in its mucous membrane, a large number of deep polygonal pits, like 

 the cells of the honey-eomb, and always contains a considerable quantity of 

 liquid. There is a very free communication between the reticulum and the ru- 

 men. The third stomach, called the omasum, or psalterium, is ovoid in form, and 

 its mucous membrane is arranged in folds like the leaves of a book, giving it a 

 very remarkable appearance. These folds are alternately wide and narrow. 

 The fourth stomach, called the abomasum, is the true secreting organ. It is lined 

 by a soft, glandular mucous membrane, and resembles the single stomach of 

 most mammals. In the camel, in addition to the above compartments, the 

 stomach is provided with several groups of large sacs attached to the rumen. 

 These receive only liquids, and are provided with bands of muscular fibres around 

 their openings, so that their liquid contents may be retained and stored up for 

 future use. In this animal, the cells of the reticulum are unusually deep, narrow 

 at their openings, and are capable of being closed by the contraction of mus- 

 cular fibres situated at their orifices. 



