Supplementary Chapter 323 



by films of nitrocellulose, cellulose itself (from viscose) in the 

 form of film and threads gelatin, and other colloids. The 

 effects observed are relatively specific for celluloid. They have 

 been studied in relation to rates of absorption, equilibrium, and 

 rates of diffusion, and referred to * dispersivity,' i.e. the ratio 

 of surface to volume (of the colloid medium). 



The main conclusion from the data obtained is that the 

 initial and main effect is due ' to some easily available surface 

 between gas and film.' The surface between disperse and con- 

 tinuous phase is no doubt also involved. 



It will be noted that investigations of the physical properties 

 of cellulose have been sporadic, and the records are scattered 

 over a range of subjects not obviously related through their 

 titles. The authors are engaged in collecting and revising 

 these from the point of view of this section, and as a step to 

 definite progress in the most neglected and at the same time 

 most promising field of research. 



Lignocelluloses. From a series of published investiga- 

 tions referred to in the preface to the 1916 edition, the follow- 

 ing may be inferred as to the generally accepted present state 

 of knowledge and progress. The most characteristic reaction 

 is that of chlorination, which is simple in the case of the ligno- 

 celluloses of annuals ; the chlorination being attended by the 

 formation of an equivalent quantity of hydrochloric acid. 



In the lignocelluloses of perennials (woods) the proportion 

 of chlorine appearing as hydrochloric acid is a multiple (>3) 

 of the chlorine combining with the lignone. This may be 

 referred to oxidation of a constituent group. 



Heuser and Sieber (loc. tit?) in studying the exhaustive 

 chlorination of pine-wood established the actual figures as : 



Cl combining 9*5 p.ct. of the lignocellulose 

 Cl as HC1, 31*3 n ii 



