96 THE NATUUK AND TREATMENT OF 



descended. These intermediate deglutitions going on without 

 s^nj cessation of mastication, we have shown that they com- 

 mence immediately the cud has entered the mouth, and are in- 

 voluntary, their number varying from two to three, rarely being 

 four. One or two happen consecutively ; but it is rarely we 

 reckon four- during the mastication of the cud. If at this time 

 the ear be applied to the left side of the pharynx, borborysm is 

 heard at the time deglutition takes place, when the cud ar- 

 rives in the mouth, at the very moment even that it is passing 

 over the isthmus of the throat. In general, the quantity of 

 fluid which ascends along with the cud, in order to facilitate its 

 passage and prove effective for ruminatory mastication, is con- 

 siderable, especially when animals are fed on green forage or 

 roots. 



" M. Colin asserts that no more than four or five seconds elapse 

 between the deglutition and rejection of the cud, but does not 

 inform us how such calculation is arrived at. To properly es- 

 timate the time, we should reckon the number of seconds inter- 

 vening between the cessation of mastication at the moment of 

 voluntary deglutition, and the return of a fresh cud into the 

 mouth to be masticated. And short as is this interval, yet it is 

 divisible into three acts : the descent of the chewed cud ; the 

 formation of a fresh cud ; and the ascent of the last. 



" We can understand its being necessary that the swallowed 

 cud should pass first through the oesophagus to have the passage 

 free for the new cud ; in the course of which passage it is that 

 the latter obtains its formation. To say that the cud is seized 

 and rejected by the oesophagus, is to convey false notions. There 

 is in operation, in all the parts concerned, a continuity/ of con- 

 traction which sets aside all notion of independent action ; which 

 successive contractile force now and then becomes expended, as 

 we have seen in the stoppage of the cud in the middle of the 

 neck ; whence it again, instead of passing upward, descends. 

 We can, as we have likewise seen, should the cud remain in 

 arrest, by pressure, cause its re-descent ; but when once it has 

 become sufficiently masticated, give what pressure we may, we 

 cannot force the cud in the reverse direction, upward, towards 



