124 



KUMINATION. 



■substances being returned tlirougli the oesophagus to the mouth 

 by the contraction of the muscle fibres of the tube, assisted bv 

 the action of the midriff or diaphragm, which presses on the 

 rumen, contracting its size and forcing the contents into the 

 oesophageal groove to the gullet. The other portion passes on 

 to the reticulum, some even entering the third stomach or 

 •omasum, without passing through the second stomach. In the 

 Teticulum the contents are subjected to pressure, extracting the 

 liquid portion, which passes on to the third and fourth stomachs, 



,m: 



(FllOM Chauveau's Anatomv.) 



iscctfon of the VXM of the Omasum of the Sheep, ^rom the 6reat Curvature, Shovrfng 

 the Origin of the Leaves. 



P — Peritoneum. M — The two muscular layers. E — Epithelium. 1, 1— Principal 

 leaves at their orig'in. 2 — Secondary leaf, 3,3 — Leaves of the thirtl order. 4— Den- 

 liculated lamina. 5,5 — Two planes of muscular fibres ascending- into the principal 

 leaves, some issuing- from the muscular layer of the organ. 



the solid, dry residue being taken up by the oesophagus and re- 

 turned to the mouth to be re-masticated, proving that it is not 

 ■only the contents of the rumen which enter into rumination, 

 but those of tlie reticulum as well. The oesophagus in ruminat- 

 ing animals having a double duty to perform, is proportionately 

 supplied with muscles. Especially is this the case around its* 

 ]ower portion, where the bolus is first seized to be returned to the 



