THE DISEASES OF CATTLE. . 95 



" As to unilateral mastication, the jaw, like other parts of 

 the bodj, is not symmetrical in its operation ; its action, owing 

 to various causes, may be more energetic on one side than en 

 the other. Nor need we say that mastication will be prolonged 

 by certain kinds of food, by age, etc., or that it will be com- 

 paratively tardy or rapid at one time to what it is at another, 

 owing to similar obvious causes. It may likewise be inter- 

 rupted by any thing alarming the animal, or provoking his at- 

 tention during the act ; and whenever he finds it impossible to 

 continue mastication, with an effort he swallows the cud. We 

 have seen the cud re-ascend into the gullet, and no sooner be- 

 come lodged there than redescend again into the stomach ; as 

 though the contractile force which has caused its ascent so far 

 had become expended at that spot. And we have reproduced 

 the same phenomenon by counteracting, by vigorously seizing 

 hold of the oesophagus with the hand, the contractile force 

 which caused the cud to ascend, and this has been followed by 

 its redescent. But where to ? Into the rumen, the reticulum, 

 or the manyplus ? We can answer only by hypothesis. It is 

 probable that such aliment as had not received sufficient 

 attrition should fall back into the first two compartments, such 

 parts as contained the most fluid passing into the reticulum, those 

 the most solid into the rumen. 



*' The deglutition of rumination is attended with a remarkable 

 phenomenon. While it is going on, and the aliment is being 

 subjected to the action of the jaws, a motion is perceptible 

 along the oesophagus. M. Colin asks the reason for this ? In 

 our opinion it is owing to the involuntary deglutition of liquid 

 matters left in the back of the throat by the passage of the cud. 

 In proof whereof comes the shortness of the interval between 

 the commencement of mastication and this perceptible motion. 

 At the time the aliment is re-ascending into the mouth, there is 

 to be heard along the oesophagus a gurgling sort of noise ; in 

 some cases it amounts to a kind of eructation. The cud no 

 sooner reaches the oesophagus than there comes to be seen, after 

 a slight catch {souhresant), a fresh cud re-ascending to the 

 mouth with a speed nearly equal to that with which the other 



