GASTRIC DIGESTION. 377 



the contents of the reticulum into the manyplies. The entrance of the 

 contents of the rumen through the contraction of its walls into the 

 reticulum leads to a contraction of the muscular walls of this compart- 

 ment, and the materials contained in it are thrown up against the edo-es 

 of the oesophageal gutter. Through this contact the oesophageal pillars 

 shorten so as to draw up the opening into the manyplies nearer to the 

 reticulum, at the same time turning spirally on their own axes the left- 

 hand pillar being extended downward and to the right. The contents 

 of the reticulum thus find a means of ready entrance into the manyplies 

 large particles being strained off by the papilla; at the orifice of the 

 manyplies, and falling back into the reticulum. 



Although the reticulum receives all the matter swallowed, its small 

 size prevents it from retaining more than a small portion, the remainder 

 being forced into the rumen and manyplies, the fluid and finely divided 

 solids alone entering into the latter on account of the small size of the 

 communicating orifice. Its function, therefore, is to assist in rumination, 

 particularly by supplying the fluids which ascend the oesophagus, and by 

 its contraction aiding in the ascent of the cud and in keeping up the 

 circulation between the contents of the first and second stomachs. It 

 also has no secretion proper, and the fluids found in it have the same 

 source and same functions as those found in the rumen. 



If one could judge of the importance of an organ bj r its complexity, 

 the functions of the psalter would play an especially important role in 

 the gastric digestion of the ruminant. In this compartment of the 

 stomach the openings are always narrow, are always close together, and 

 are both on the uppermost portion of this organ, while the free borders 

 of its folds are directed downward ; consequently, the manyplies, by 

 means of its folds and the narrowness of its openings, the one into the 

 fourth stomach being closed by a powerful muscle and numerous large 

 papillae, like a sieve, strains off solids and delays the passage of aliments 

 into the true stomach. The muscular fibres which run in the larger 

 folds are inserted into the borders of the orifice between the manyplies 

 and reticulum. When, therefore, the sphincter-muscle of this opening 

 contracts, after the entrance' of the contents of the reticulum, the folds 

 are simultaneously drawn up, and the food is thus forced up to the base 

 of these partitions. At the same time, through the contraction of its 

 walls, the posterior extremity is drawn forward so that the prolongation 

 of the oesophageal canal becomes almost perpendicular to the opening of 

 the third into the fourth stomach. By this process not only the fluid in 

 the oesophageal canal, but a portion of the food previously in the many- 

 plies may enter the rennet. The contraction of these folds does not take 

 place only during rumination, but also during its intervals ; the water in 

 the contents of this compartment is then pressed out, and the residue 



