STOMACHS OF MAMMALIA. 1 (J9 



It would appear that the first changes which 

 constitute digestion take place principally at the 

 cardiac end of the stomach ; and that the mass of 

 food is gradually transferred towards the pylorus ; 

 the process of digestion still continuing as it ad- 

 vances. In the Rabbit it has been ascertained that 

 food newly taken into the stomach is always kept 

 distinct from that which was before contained in it, 

 and which has begun to undergo a change : for 

 this purpose the new food is introduced into the 

 centre of the mass already in the stomach : so that 

 it may come in due time to be applied to the coats 

 of that organ, and be in its turn digested after the 

 same change has been completed in the latter.*" 



As the flesh of animals has to undergo a less 

 considerable change than vegetable materials, so 

 we find the stomachs of all the purely carnivorous 

 tribes consisting only of a membranous bag, which 

 is the simplest form assumed by this organ. But 

 in other cases, as we have already seen, the sto- 

 mach exhibits a division into two compartments, 

 by means of a slight contraction ; a condition which, 

 as Sir E. Home has remarked, is sometimes found 

 as a temporary state of the human stomach ;| while, 

 in other animals, it is its natural and permanent 

 conformation. The Rodentia furnish many exam- 

 ples of this division of the cavity into two distinct 

 portions, which exhibit even differences in their 

 structure : this is seen in the Dormouse, (Fig. .300) 

 the Beaver, the Hare, the Rabbil, and the Cape 



* See Dr. Philip's Experimental Enquiry into the Laws of the 

 Vital Functions, 3d edition, p. 122. 



t The figure given of the human stomach, p. 182, shows it in the 

 state of partial contraction here described. 



