{4 STRUCTURE AND OFFICE OF THE STOMACH. 



the stomach responds much less with the kind of teeth, than it haa been 

 to^tha" of the generally supposed to do. The animals with chissel teetli 

 teeth than have no uniformity in the structure of their stomachs ; those 

 supposed^ ®^ *^* beaver and dormouse being of one kind ; the hare's 

 and rabbit's of another; the squirrel's of a third, resembling 

 that of the monkey ; the guinea pig's of a fourth, differing 

 from that of the squirrel, in there being a greater dispropor- 

 tion between the thickness of the coats of the cardiac and 

 pyloric portions; the rat tribe of a fifth, which resembles 

 the stomach of the horse and ass, animals whose teeth have 

 a very different form. 

 Greater analo- On the other hand, all the ruminants with horns have one 

 fiomadi^^r^ structure of stomach ; all those with fighting teeth another, 

 weapons of dc- as has been observed in a former paper; also all the animals 

 ence. ^-^^^ projecting tusks have the pouches at the cardia, which 



appear to be peculiar to them, although there is no connec- 

 tion we yet know of between these weapons of defence and 

 the stomach. 

 Elephant. As the elephant's grinding teeth are the best fitted for 



preparing vegetable food for digestion, so the stomach in its 

 structure approaches nearer to those of carnivorous ani- 

 ,f mals. 



The stomachs of which the structure has been hitherto 

 considered belong to animals that feed on vegetables, and 

 chiefly on the leaves, roots, and branches of plants. In the 

 AnimaU that gradation towards carnivorous stomachs, we are next to take 

 feed o"""its. jjQ^pg Q^- ti^^ge ^j,at belong to animals whose principal food 

 is the fruits of tjees, which appear to require less preparation 

 for the process of digestion ; of this kind are the stomachs of 

 the squirrel and monkey. These in their general appear- 

 ance resemble very closely the human stomach ; at least the 

 few opportunities, which have occurred to me of examining 

 them, have not enabled me to detect any circumstances in 

 which they differ. 

 Human sto- The human stomach appears to be the uniting link be- 

 mach. tween those that are fitted only to divest vegetable sub- 



stances, and those that are entirely carnivorous ; and yet we 

 find in its internal structure it is in every material respect 

 similar to those of the monkey and squirrel, which only di- 

 gest vegetable productions, and also equally similar to those 



of 



