62 THE CARBOHYDRATES. 



lytic decomposition the common cellulose yields glucose, while the 

 so-called hemicelluloses give rise to galactose or mannose, as also to 

 -certain pentoses, such as arabinose and xylose. In the intestinal 

 canal a certain portion of the ingested cellulose is unquestionably 

 dissolved. The products, however, to which it gives rise are for the 

 most part unknown. Certain micro-organisms which are present at 

 the time bring about a fermentation of the substance, during which 

 marsh gas, acetic acid, and butyric acid are formed, but the greater 

 portion no doubt is eliminated in the feces as such. 



