96 Cellulose 



oxidising solutions, treated with sulphurous acid on the filter, 

 well washed with water, squeezed, dried and weighed. 



The cellulose estimations by this method give what may be 

 considered the maximum yield ; other methods attack the 

 /3-cellulose more or less, giving products which are dissolved 

 and removed. These methods may be briefly noticed. 



(2) Bromine water (Hugo Miiller). This halogen, and in 

 the form of aqueous solution, fails to saturate the R. 

 hexene groups in one operation ; hence the alternate treat- 

 ment with bromine water in the cold, and boiling alkaline 

 solution, requires to be once, twice, or even three times 

 repeated. The yield of cellulose is 2-5 p.ct. lower, and 

 the process is by comparison tedious. 



The difference in yield is -due to the attendant oxidation 

 and hydrolysis of the /3 -cellulose. 



The following experimental determinations bear upon this 

 point : 



A specimen of jute gave the following percentages of cellulose 

 under various methods of treatment : 



(0 73-74 P-ct. Bromine water (cold) and boiling aqueous 

 ammonia alternately till pure. 



(2) 74-76 p.ct. Chlorination at ordinary temperatures, fol- 

 lowed by alkaline hydrolysis. 



(3) 8o '9 8o '6> 79'9> 82-0, 81-3, 84-5, in individual experiments in 

 which the treatments were varied as follows : (a) chlorination at 

 0-5 ; (b) followed by digestion in dilute sulphurous acid at 0-5 ; 

 (c) hydrolysis with sodium sulphite solution, at first cold, afterwards 

 raised to boiling. 



From-these results it appears that, by excluding oxidising con- 

 ditions and graduating the hydrolysis of the chlorinated derivative, 

 a considerable proportion is separated in the form of fibrous cellu- 

 lose ; this portion, under other conditions, is hydrolysed to soluble 

 derivatives. 



(3) Nitric acid and potassium chlorate (Schulze). This 

 method consists in a prolonged digestion 10-14 days) of 



