ORGANS OF DIGESTION. 319 



the CBsophagean canal. The entrance, however, to the third 

 commences before the opening into the second' stomach 

 ceases. The entrance to the fourth stomach is two inches 

 and a half in extent, and is formed by duplications of the 

 mucous and muscular coats of this viscus, which meet so 

 as to close the entrance when either the will of the animal 

 or the necessity of nature requires. 



The usual course of the food is into the rumen or first 

 stomach, whose entrance is close to the termination of the 

 oesophagus and thp entrance of the canal. This stomach is 

 of enormous extent, occupying, indeed, when full, nearly 

 three-fourths of the abdomen. It lies towards the left side 

 extending to the flank, and by a sort of muscular band it is 

 partially divided into two principal compartments. It is 

 lined externally by the peritoneal membrane, in common 

 with the other contents of the abdomen, and internally by 

 an insensible membrane, called the cuticular, between which 

 there are two other coats — ^the mucous, which secretes the 

 fluid found in the stomach, and external to this the muscular 

 coat, which is formed of two orders of fibres running in op- 

 posite directions. Its interior aspect presents a number of 

 pouches or compartments, which are formed by muscular 

 bands thrown across from one part to another ; and the sur- 

 face presents an innumerable number of papillae or eminen- 

 ces, not sharp, but blunt-pointed, which are formed by the 

 mucous coat and merely covered by the cuticular. These 

 papillae are coarser in the lower compartment of the viscus 

 than in the upper. We hai^ said the rumen consists of two 

 compartments, but with greater propriety it may be stated 

 that there are three, a smaller one being situated immediately 

 below the termination of the cesophagus and adjoining the 

 second stomach. The use of these partial divisions is very 

 evident. They relieve one portion of the stomach from sus- 

 taining the whole of the weight of the food, and they afford 

 a sort of steps or resting-places for the food that has under- 

 gone maceration, the upper and smaller compartment being 

 that into which the food is raised just previous to being ru- 

 minated. The rumen is partly attached to the second stom- 

 ach, but only communicates with it through the common 

 opening into the oesophagean canal. 



The second stomach is called the reticulum; its size is 

 considerably less than the rumen, biit it possesses much 

 •trength in its coats, and its muscular fibres are more devel- 



