DISAPPEARANCE OF VEGETABLE FIBRES 199 



Haubner, Henneberg and Stohmann, v. Hofmeister, Weiske, 

 Knieriem and others left no doubt that in vegetarians a 

 portion of the ingested " coarse vegetable fibre " (a mixture 

 of celluloses, hemicelluloses, pentosans, lignin and similar 

 substances remaining after exhausting vegetable food with 

 dilute acids, caustic soda, alcohol and ether) actually disap- 

 pears in the intestine. 16 We are not dealing here with a 

 subtile matter, but on the contrary with decidedly gross 

 relations in that the fraction of the ingested cellulose which 

 vanishes within the digestive tract and fails to appear in the 

 excrement in the herbivorous domestic animals is estimated 

 to amount to from 30 up to 70 per cent. The degree to which 

 it can be used in the body depends upon the character of the 

 cellulose. That of hay and still more that of tender young 

 plants is more readily handled than, for example, is that of 

 the bran of oat-seed and of barley, which is practically or 

 entirely indigestible. Surprisingly, birds, even the typical 

 graminivorous species, seem entirely unable to digest cel- 

 lulose; W. Biedermann 17 believes this is perhaps explicable 

 by the thought that birds which live upon vegetable food 

 generally possess a powerfully developed muscular stomach, 

 by which they are mechanically able to break up into fine 

 bits the seeds they swallow without the need of chemical 

 solvents for the cellulose of the hulls. The ability to digest 

 cellulose is entirely absent from the carnivorous animal, 

 especially the dog ; this may be looked upon as settled by the 

 studies of Scheunert and others after much controversy. 18 

 Man is apparently to be classed among the vegetarian 

 animals from his position in relation to cellulose. It is 

 said that about 50 per cent, of the cellulose and hemi- 



10 Literature upon Cellulose Digestion: A Scheunert, Handb. d. Biochem., 

 3", 134-138, 1909; W. Biedermann, Handb. d. vergleich. Physiol., 2' 1314-1344, 

 1911. 



"W. Biedermann, 1. c., p. 1314. 



18 A. Scheunert and E. Lotsch, Berl. tierarztl. Wochenschr., 1909, No. 47 ; 

 Zeitschr. f. physiol. Chem., 65, 219, 1910; Biochem. Zeitschr., 20, 10, 1910; 

 H. Lohrisch, Zeitschr. f. physiol. Chem., 69, 143, 1910; H. v. Hosslin (Med. 

 Clinic, Halle), Zeitschr. f. Biol., 54, 395, 1910. 



