Compound Celluloses 117 



This phenomenon, already described as a property of the cellu- 

 loses, is more pronounced with the jute fibre. The following 

 absorptions have been determined by the authors from normal 

 solutions of the respective reagents : 



Normal hydrochloric acid. (a) Fibre digested with 8 

 times its weight of solution, 10 minutes at 15 C. ; (b) with 20 

 times its weight. 



(a) ' (b) 



HC1 absorbed . 0-85 i-i p.ct. on fibre-substance 



Normal sodium hydrate. Fibre digested with 20 times 

 its weight of solution. 



() (*) 

 Na,jO absorbed . .3-0 3-6 p.ct. on fibre-substance 



It is to be noted that the molecular ratio of the absorptions 

 is approximately that observed in the case of cotton, viz. 

 3HC1 : 10 NaOH. 



The hydrolysing action of the alkalis (a) and non-oxidising 

 acids (b) may be regarded as an extension of this phenomenon. 

 (a) The alkalis and alkaline compounds in aqueous solution 

 attack the fibre-substance in the ratio of their hydrolysing and 

 saponifying activity ; and, as in the action of the solvents pre- 

 viously described, the lignocellulose is attacked as a whole. 

 In the systematic comparison of the vegetable fibres (i.e. com- 

 pound celluloses) it is important to determine their relative 

 resistance to alkaline treatments under standard conditions. 

 It is usual, for this purpose, to determine the loss of weight 

 sustained by the fibre on boiling with a i p.ct. solution of 

 sodium hydrate (i) 5 minutes, (ii) 60 minutes. Under this 

 treatment jute loses on the average 



(i) (M) 



8-0 15-0 



No change in the composition of the fibre- substance is 

 occasioned by the treatment, the portion dissolved showing the 

 essential characteristics of the original fibre. It is precipitated 



