136 THE CARBOHYDRATES 



Cellobiose reduces Fehling's solution and gives an osazone, 

 m.p. 208-210". 



3. Oxidizing Agents. — Dilute solutions of alkaline hypo- 

 chlorites have very little action on typical cellulose, and can 

 therefore be employed for bleaching this material ; with con- 

 centrated solutions of hypochlorites, however, a general decom- 

 position ensues. As already mentioned, nitric acid (sp. gr. 

 I "25) at 180° converts cellulose into a series of oxidation 

 products known as oxycellulose, and similar substances are 

 produced by the action of other oxidizing agents, such as 

 chromic acid, potassium chlorate, and hydrochloric acid, etc. 

 The nature of these oxycelluloses differs somewhat according 

 to their mode of formation, but in general they are charac- 

 terized by the fact that they yield a relatively large amount ot 

 furfurol on boiling with hydrochloric acid ; they are hydro- 

 lized by boiling with milk of lime into isosaccharic and dioxy- 

 butyric acids ; they also reduce Fehling's solution, and are dyed 

 by basic dyes, such as methylene blue. 



The fact that the cellulose obtained from esparto grass 

 and cereal straws resembles oxycellulose, in yielding a con- 

 siderable proportion of furfurol on boiling with hydrochloric 

 acid, leads to the idea that cellulose from these sources con- 

 tains oxycellulose, but whether or not such oxycelluloses are 

 actually pre-existent in the plant fibre has not yet been defi- 

 nitely established (see Lignocelluloses). 



4. Action of Fermejits. — It has been shown by Brown and 

 Morris, in the case of malt, that the cell wall of the endosperm 

 cells which contain nutrient material are broken down by a 

 cellulose-dissolving ferment, a cyto-hydrolyst, before the 

 embryo can procure the food-stuff contained in these cells. 

 This enzyme, which is developed during the germination of 

 the seed, can be extracted from the malt by cold water, and 

 precipitated from this solution by alcohol. As another ex- 

 ample of the fermentative decomposition of cellulose may be 

 quoted the formation of marsh gas according to the equation 



CsHioOb + H„0 = 3CO2 + 3CH, 



which may be observed when vegetable matter is undergoing 

 slow decomposition under stagnant water. 



