Experimental and Applied 297 



lowing were cited by Witz as typical. The oxycelluloses show 



An increased attraction for 

 Methylene blue 

 Hofmann violet 

 Malachite green 

 Safranine red 

 Fuchsine red 

 Bismarck brown 



A diminished attraction for 



Diphenylamine blue, sulphuric 



acid 



Induline blue, sulphuric acid 

 Indigo sulphonate 

 Tropaeoline orange 

 Eosine red 



in comparison with the cellulose. (See Bull. Soc. Ind. Rouen, 

 [10] 5, 416 ; [n] 2, 169 ; Dingl. J. 250, 271 ; 259, 97 ; J. 

 Soc. Chem. Ind. 1884.) 



Here also structural factors are eliminated, and the vari- 

 ables are again constitutional. 



Selective attractions of more narrowly specific character are 

 exhibited, on the other hand, by both the celluloses and ligno- 

 celluloses, of which typical instances may be discussed. 



Thus, in the case of the celluloses, modern discovery has 

 added to the coal-tar dyes a number of compounds which dye 

 cotton directly to full shades, and are therefore known as 

 cotton colours. Although, however, these are synthetic pro- 

 ducts, and therefore bodies of known constitution, no general 

 constitutional relationship of these compounds has yet been 

 established such as to account for their * specific affinities ' to 

 the celluloses. This, of course, complicates the phenomena, and 

 shows that other factors, in addition to those of constitution as 

 ordinarily understood, contribute to the result. Of such we 

 may instance as probably operative the molecular condition of 

 the colouring matter in aqueous solution. 



Of all the colouring matters having this particular relation- 

 ship to the celluloses, the most noteworthy is the dye-stuff 

 known by the trivial name 'primuline,' a complicated colour-base 

 derived from thiotoluidine.. The sulphonic acid of this highly 

 * condensed ' product combines freely with cellulose when the 

 latter is treated with its dilute aqueous solution as in ordinary 



