Supplementary Chapter 315 



discrimination of cellulose characteristics or quality. The 

 normal cellulose is regenerated quantitatively ; other celluloses 

 are partially resolved into alkali- soluble forms. The viscose 

 cycle, however, is of composite character, and as we have postu- 

 lated simplicity, the process of acetylation controlled as regards 

 temperature and selection of catalyst will commend itself on 

 general principles, and for the special reasons already enu- 

 merated. We have, moreover, furnished experimental evidence 

 of its diagnostic value as a measure of changes determined by 

 so apparently colourless a procedure as boiling cellulose with 

 1 pure ' water. 



The following conclusions may be noted for research 

 work on cellulose. The forms of bleached cotton generally 

 adopted e.g. more particularly chemical filter-paper or surgical 

 cotton-wool are not admissible as normal standard cellulose. 

 It is an inevitable point in methodical accuracy to select a 

 cotton of which the chemical history, from the raw to the 

 bleached state, is known. In every case the actual state of the 

 cellulose should be diagnosed in quantitative terms as regards, 

 that is, resistance and reactivity, by treatment with processes 

 under (i) or (2) indicated above. 



Since every process of treating the vegetable fibres in the 

 arts produces some constitutional change, it is a necessary 

 basis* of scientific progress in these arts to ascertain what these 

 changes are, so that effects may be measured and controlled in 

 terms of a more exact knowledge of the substance, i.e. as a 

 chemical individual. Notable advances in the practice of the 

 textile bleacher and finisher, dyer and printer, and the paper- 

 maker must follow the methodical study of the basis of 

 their arts. The industrial production of artificial modifications 

 of the original celluloses, produced by way of synthetical 

 derivatives, depends more obviously on scientific method ; but 

 even in these branches there is need of revision of empirical 

 standards. 



