Nitrogen -free Extract Vegetable Gums 79 



nitrogen -free extract of the entire plant was found to 

 be starch and sugars. The other half evidently con- 

 sisted of bodies either not so well known or not known 

 at all. 



Among the less familiar compounds which we now 

 recognize as existing quite abundantly in the stem and 

 leaves of many, if not all, fodder plants are the vege- 

 table gums, some of which are designated by the 

 chemist as pentosans. Only a few such substances 

 are definitely known, one of which, araban, is con- 

 tained in gum arabic, gum tragacanth, cherry gum, 

 beet pulp, and doubtless in various other materials; 

 another being zylan or wood gum, which may be sep- 

 arated in abundance from wood and straw. Stone has 

 examined "a large number of agricultural products for 

 these gums, and if present methods of analysis are 

 accurate, he found in the dry matter of such feeding 

 stuffs as hays from several species of grass, corn fod- 

 der, sugar beets, rutabagas, wheat -bran and middlings 

 and gluten meal from 6 to over 16 per cent, the high- 

 est proportions appearing in timothy hay, corn fod- 

 der, and wheat -bran. In mature field -corn fodder 

 he obtained about 16 per cent, thus accounting for 

 about half of the nitrogen -free extract left after sub- 

 tracting the starch and sugars. Wheat bran contained 

 much more than middlings, and the least was present 

 in gluten meal. These gums are surely much more 

 abundant in the coarse foods than in the grains, a 

 fact which, as we shall learn, is important in com- 

 paring the nutritive value of different classes of feed- 

 ing stuffs. 



