ALIMENTARY CANAL OF ARTIODACTYLA. 477 



The herbivorous Mammals differ from the carnivorous more in 

 the character of their large than of their small intestines. The 

 less putrefactive nature of their food renders it susceptible of a 

 longer retention in the body ; and the receptacular and sacculate 

 structures, and convolute extension, of the large intestines seem 

 especially designed to retard the course of the alimentary sub- 

 stances. In the anomalous instance in a Human body, recorded 

 by Abernethy, of a reduction of the length of the small intes- 

 tine to about two feet, the compensation was effected by an un- 

 usual length and size of the colon. The condition of the subject 

 ' showed that nutrition was not scantily supplied.' l Dupuytren 

 noticed in a patient who had an artifical anus near the end of the 

 small intestines, that the vegetable parts of the food thence 

 ejected were undigested. Dr. Beaumont also observed that the 

 vegetable substances underwent much less change than the 

 animal substances in the stomach of the man (Alexis) with the 

 fistulous opening into the stomach. That organ in the Artio- 

 dactyles (Peccary, Hippopotamus, and Ruminants) is rendered 

 specially complex for overcoming the difficulty, and the caecum 

 and colon are comparatively small : but in the Perissodactyles 

 (Horse, Tapir, Rhinoceros) the more simple stomach is compen- 

 sated by the increased capacity and complexity of the large 

 intestines. The subdivided stomach in the Sloths is in some 

 respects, as e. g. the glandular appendage, and vascular secern- 

 ing surface of the paunch, more complex than that of Ruminants : 

 and here accordingly we find the caecum absent and the colon 

 undefined. The Dormouse and other hybernating Rodents are 

 far from being the sole exceptions to the presence of a propor- 

 tionally large caecum in herbivorous quadrupeds ; such receptacle 

 is only found in those species, in which, through the necessity of 

 a correlation with other circumstances than that of the nature of 

 the food, the stomach retains the simple form and moderate size 

 of that of the carnivorous or omnivorous mammals. Comparative 

 Anatomy demonstrates that neither a complex stomach nor a large 

 caecum is essential to the digestion of vegetable food: but it 

 teaches that a capacious and complex alimentary canal, as a whole, 

 is related to that purpose, at least in the Mammalia. Either a 

 highly-developed and concentrated glandular apparatus must be 

 added to the stomach, as in the Dormouse, Wombat and Beaver : 

 or the stomach must be amplified, subdivided or sacculated, as in 

 the Ruminants and herbivorous Marsupials ; or both complexities 

 must be combined, as in the Sloths, Dugongs and Manatees ; or, 



1 cxlvi". p. 63. 



