128 



Cellulose 



either of the chloride or the ferricyanide by the fibre-substance 

 will be found to be inadequate. The following experiments 

 show that either reagent taken singly is but slightly affected by 

 prolonged contact with the fibre-substance. 



Equal weights (2*835 g rms -) of the purified fibre were 

 placed 



(a) In a solution (30 c.c.) of FeCl 3 1*6 grm. per 100 c.c. 



(b) In a solution (30 c.c.) of K 3 FeCy 6 3*3 grms. per 

 100 c.c. 



(c) In a solution prepared by mixing the above (30 c.c. of 

 each). 



After standing some hours (a) and (b) were squeezed and 

 interchanged, and left some minutes. The fibre from each 

 was then washed off, dried, and weighed with the following 

 results : 



It appears, therefore, that the lignocelluloses absorb but 

 little 1 oxide from a neutral solution of ferric chloride, and 

 there is only partial reduction of the oxide so fixed : and also 

 that ferricyanide is slightly reduced by the fibre- substance in 

 neutral solution and without sensible combination with the 

 ferricyanogen or ferrocyanogen group. 



The reaction in question is therefore specific as between 

 the ferric ferricyanide and the fibre-substance. 



That the formation and fixation of the blue product is not 

 the result of reduction in the liquid is further shown by the fact 



1 The maximum we have observed to be taken up from a normal solu- 

 tion of the chloride is 0-4 p.ct., and that after 48 hours' immersion. 



