13S 



.4 Manual of Veterinary Physiology. 



In those animals where vomiting is a natural process, the 

 three important operations are the dilatation of the cardia 

 by active contraction of the longitudinal fibres of the 

 oesophagus, pressure on the walls of the stomach by the 

 abdominal muscles, and closure of the pylorus. 



Rumination. 

 The physiology of rumination has been principally 

 worked out in France by Flourens and Colin, and our 

 knowledge of this singular process is based entirely on 

 their observations. 



Fig. LO.— Diagram op the (Esophageal G-roove. 



03, oesophagus entering the stomach ; c, its cardiac opening ; RP, right 

 pillar of oesophageal groove ; LP, left pillar of the same ; 0, open- 

 ing into the omasum ; GBG, oesophageal groove extending from 

 c to o. To the right of the figure is the rumen, to the h-i't the 

 reticulum. (After Carpenter.) 



The oesophagus in ruminants enters the rumen and forms 

 a singular groove or channel known as the oesophageal, 

 which on the left communicates with the first and second 

 stomachs, and on the right, by a very small opening, with 

 the third stomach (Fig. 10). In this way food coming 

 down the oesophagus may enter either of the three first 



