Experimental and Applied 255 



papers (loc. cit.\ and to repeat the experimental demonstrations 

 therein given, of the formation of these oxycelluloses, and the 

 methods of diagnosing their presence in textile fabrics. 



It is to be noted that the ordinary bleached celluloses of the 

 cotton group all give a small proportion of furfural (0-3-1-0 p.ct.) on 

 boiling with hydrochloric acid(i'o6 sp.gr.), which may betaken as 

 indicating the presence of an oxycellulose in proportionate quantity. 

 It is probable also that the somewhat increased reactivity of 

 bleached cotton may be due to formation of oxycellulose. 



Study of Methods of Bleaching. The student should compare 

 the bleaching actions of potassium permanganate and sodium 

 hypochlorite from the point of view of bleaching effect, and 

 relative consumption of oxygen. It must be noted that the per- 

 manganate (i.e. Mn 2 O 7 ) is deoxidised to the dioxide MnO. 2 , which 

 is deposited as the brown-coloured hydrate upon the cellulose ; 

 the depth of colour is therefore a measure of the oxidation which 

 has taken place, generally or locally. The oxide is removed by 

 treating the substance, after washing from the alkali simultaneously 

 set free, with a solution of sulphurous acid, the interaction of the 

 reagents producing dithionic acid. With the disappearance of the 

 brown oxide the bleaching effect produced by the original oxidation 

 is at once apparent. 



While the action of the permanganates upon the cellulose is 

 necessarily that of simple oxidation, the hypochlorites may act in 

 two ways: (i) a simple oxidation; (2) chlorination. The latter 

 effect is usually small, the proportion reacting in this way depend- 

 ing upon the temperature of the solution and also the nature 

 of the base with which the hypochlorous acid is combined. See 

 * Some Considerations on the Chemistry of Hypochlorite Bleaching ' 

 (J. Soc. Chem. Ind. 1890). 



Formation of Acetic Acid from Cellulose. The student should 

 read the account of a systematic investigation of these reactions by 

 J. F. V. Isaac and the authors (J. Soc. Chem. Ind. 1892). 



The maximum yields of 30-40 p.ct., which are obtained under 

 the most favourable conditions, point to a CO CH 2 ' residue ' in 

 the cellulose molecule itself, as the immediate source of the acetic 

 acid. 



Ferment-hydro lyses of Cellulose. It is obvious that chemical 

 compounds destined to transmit, accumulate,, and otherwise respond 



