tS STRUCTURE AND OFFICE OF THE STOMACH. 



the food is macerated, before it is stibmitted to the process 



of digestion. Animals of this kind are the water rat, in 



which there is a permanent division between tne cuticular 



Common rat cavity and the dij^stive part of the stcwnach ; the common 

 and mouse. ^ j .1 • i • 1 .1 • , 



rat and the mouse, m winch there is only a muscular one. 



The cuticular lining is thick and impervious ; beyond it is a 

 glandular part, that secretes a mucus found adhering to its 

 surface; and farther on ai-e oriiices, which appear to belong 

 to the solvent glands. These animals do not ruminate, and 

 there is a kind of provision in nature to prevent regurgita- 

 tion of the food. When kept without food for several dajs 

 they completely empty their stomachs, 



Horsie and ass. The horse and the ass, although animals, in all other re- 

 spects different, correspond so very closely in the structin*e of 

 their stomachs with the rat and mouse, that their stomachs 

 piustbe considered of the same kind. 



In these the food is rendered easy of solution by re- 

 maining in the cuticular reservoirs; it is then acted on by 

 the solvent liquorj and in the pyloric portion converted into 

 chyle. 



Jwanguroft. The stomach of the kangaroo, from the pecuharities of 



its structure, forms an intermediate link between the sto- 

 .machs of animals which occasipnally ruminate, those which 

 have a cuticular reservoir, and ^ third kind not yet noticed, 

 with processes or pouches at their cardiac extremity, the in- 

 ternal membrane of which is rnore or less glandular. The 



Oecasiorally l^anguroo is found tp ruminate, when fed on hard food. 



ruminates. This was observed by Sir Joseph Baj:iks, who had several qf 

 these animals in his possession, and frequently amused him- 

 self in observing their habits. It is not however their con^ 

 stant practice, since those kept in Exeter Change have not 

 been detected in that act. This occasional rumination con- 

 nects the kanguroo with the ruminant. The stomach hav- 

 ing a portion of its surface covered by cuticle, renders ij: 

 similar to those with cuticular reservoirs; and the small pro- 

 cess from the cardia gives it the third distinctive character; 

 indeed it is so sma.ll, that it would appear placed there fpr 

 no other purpose. 



Stomach ticca- The kanguroo's stomach is occasionally divided into a 



iionailydi- greater number of portions than anyothey, since every part 

 vidvid into a p 



