COMPARATIVE DIGESTION. 117 



ing the process well known under the name of rumina- 

 tion, or chewing the cud. 



342. After the mass thus elevated, has been well ground, 

 by the molares, it is again swallowed and passed into No. 

 3, or the third stomach, the orifice of which is brought 

 forward to receive it by the action of peculiar muscles, 

 at the same time the mouths of two other stomachs being 

 closed to prevent its admission. 



343. The food is now prepared for digestion, and ac- 

 cordingly passes into the fourth stomach, when being 

 mixed with the gastric juice, it is converted into chyle, 

 which passing into the circulation, becomes the nutriment 

 of the animal. Who can examine such mechanism with- 

 out feeling astonishment and awe ; and without seeing 

 wisdom and design 1 



344. In the calf, the milk is conveyed directly from 

 the esophagus to the fourth stomach, where it is coagu- 

 lated by the gastric liquor, and then assimilated into nu- 

 triment. It is this stomach of the young animal which 

 forms the substance called rennet, and which, in conse- 

 quence of the gastric juice it contains, is universally 

 employed to coagulate the milk for the formation of 

 cheese. 



345. Relation between the Horns and Stomach. That 

 there should exist any connexion between the horns of an 

 animal and its stomach, or that the absence or presence.,; 

 of the former should indicate anything in reference OF 

 the latter, is what no one could have suspected ; and yet 

 Sir E. Home has shown that ruminants with horns, as the 

 cow, and sheep, and goat, are universally furnished with 

 four stomachs : two for preparing the food, one for rumi- 

 nation, and one for digestion, as already explained ; while 

 those without horns, as the camel, lama, and rabbit, have 

 only one preparatory stomach before rumination, which 

 answers the purpose of the two in the horned animals. 

 Why such a difference should exist in animals so nearly 

 allied in general structure and habits, is one of the mys- 

 teries of nature. 



346. Water-Cells in the Stomach of the Camel. There 



