RUMINATION. 



321 



structure. In the horse we find that a less important peculiarity is also 

 to be noticed. 



After having undergone the first and incomplete mastication, the 

 food passes into the first and second stomachs, while fluid and finely 

 comminuted food ma}; enter all four compartments, passing directly 

 into the first two stomachs, and then, by means of the oesophageal 

 gutter, into the third and even into the fourth stomach. It was be- 

 lieved formerly that the oesophageal gutter conducted fluids entirely and 

 directly into the third and fourth stomachs, but Flourens proved, by 

 making fistulous openings into all four compartments, that immediately 



FIG. 138. STOMACH OF FULL-GROWN SHEEP, INFLATED AND DRIED ; ONE- 

 FIFTH THE NATURAL SIZE. (Thanhoffer.) 



B, rumen : R, reticulum ; S. omasum : O, abomasum : c, cardia : p. pylorus : br, oesophagus ; <*, 

 cardial valve : bv, oesophageal canal ; r, pillars of the rumen ; rn, opening of the reticulum ; on, opening 

 of the abomasum ; b, valve between reticulum and omasum ; e. duodenum. 



on drinking fluids entered all four stomachs almost simultaneously. 

 When an animal drinks the water enters the paunch and the reticulum, 

 since the oesophagus enters at the junction of these two reservoirs, 

 while a small quantity of liquid enters the third stomach directl}', and 

 from there into the fourth. Moreover, the reticulum is the seat of en- 

 ergetic contractions which force a part of its contents into the rumen 

 and into the third stomach : consequently it would seem clear that the 

 largest portion of fluid enters the first two stomachs and then passes 

 through to the others, though some directly enters the third and fourth, 



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