476 



DIGESTION IN HERBIVORA. 



[BOOK ii. 



animals is, firstly, the much greater length of their alimentary canal ; 

 secondly, its enormous capacity. 



Firstly, as to length. Whilst the ratio of the length of the ali- 

 mentary canal of carnivora is to that of their body approximately as 

 4:1, and of man as 6 : 1, in the sheep the ratio is as 28 : 1, and in 

 the large ruminants as 20 15 : I 1 . 



Secondly, as to capacity. All animals whose food contains a large 

 proportion of cellulose possess an alimentary canal of remarkable 

 capacity. 



We may form some idea of this fact by ascertaining the weight of 

 the intestinal contents. Thus in the rabbit immediately after it has 

 been fed, the contents of the stomach may weigh as much as one- 

 tenth of the total weight of the body. The subjoined table, which 

 exhibits a few of the data ascertained by Colin on this subject, shows 

 clearly, firstly, the immense capacity of the whole alimentary canal 

 in some herbivora : secondly, the relatively small capacity of the 

 stomach in Solidungula (the horse) as compared with Ruminants : 

 thirdly, the remarkable capacity of the large intestine, both in 

 Solidungula and Ruminants, and its much larger capacity in the 

 former than the latter. 



TABLE EXHIBITING THE RELATIVE WEIGHTS OF THE CONTENTS 

 OF THE STOMACH AND INTESTINES IN THE HOESE, BULL, COW 

 AND BAM (ABRIDGED FBOM COLIN) 2 . 



The great capacity of the alimentary canal of herbivores is related 

 to the fact of their food containing a large proportion of undigestible 

 cellulose, so that the bulk and weight of the food which the animal 

 must daily consume in order to obtain from it the albuminous, starchy, 

 and fatty constituents which are essential to its maintenance is very 



1 C. A. Ewald, Die Lehre von der Verdauung, etc. Berlin, 1872, p. 22. 



2 Colin, Traite de Physiologic Comparee des Animaux. Paris, 1886 (see p. 900). 



