1895.] rUBLIC DOCUMENT — No. 33. 187 



crusting substances perceptibly interfere with the digestibility 

 of the xylan or araban. This has also been proved to be the 

 case with cellulose, first indirectly by Hennel)erg and Stoh- 

 mann * and later directly by F. Lehniann,f who found that 

 when the fibre w^as freed from all incrusting substances the 

 cellulose Avas practically all digestiljle. 



Stone has already shown, in case of hays, bran and such 

 fodders, that the pentosans have an average digestibility of 

 GO per cent., and our results with similar fodders simply 

 confirm his investigations. A\'ith the more concentrated 

 feeds, where little incrusting substance is present, the pen- 

 tosans are as digestil)le as any other of the fodder groups. 

 One might assume that if the pentosans were isolated and fed 

 to animals they would be fully as digestible as starch or pure 

 cellulose. 



While from 60 to 90 per cent, of the pentosans in the 

 present experiment have been removed from the digestive 

 tract in the process of digestion, it has certainly not been 

 demonstrated that they have been assimilated and have a food 

 value equal to that of starch and similar substances. In case 

 of human Ijeings El)stein has already proved to the contrary. 

 "^^'e hope to be able to throw additional light upon this point 

 in the near future. 



* Futterung der Wiederkauer, 1860. 

 t Journal f. Landw. 48, 435. 



