STAINING CELLULOSE. 55 



This method shows very well the bordered pits in a vertical 

 section of pine stem. 



CHLOR ZINC IODINE (Schnlze's Solution). 



No good working formula has been published for this 

 reagent : the points being to obtain a clear concentrated 

 solution which does not crystallize on keeping, and which 

 dissolves sufficient Iodine. 



The following will yield a permanent solution, which gives 

 good results, staining unaltered cellulose a violet-blue and 

 lignified tissue yellow. Starch is of course stained blue. 



Evaporate 100 cc. of Liquor Zinci Chloridi (B.P.) to 70 cc. ; 

 dissolve in it 10 grms. of Iodide of Potassium; then add 

 0-2 grm. Iodine : shake at intervals till saturated. 



PHLOBOGLUCIN. 



PMoroglucin, 1 grm. ; Rectified Spirit, 20 cc. ; Distilled 

 Water, 80 cc. 



Sections containing lignified tissue placed in this solution 

 for about 1 5 minutes, then treated with strong Hydrochloric 

 Acid, are stained a cherry-red colour. The depth and distri- 

 bution of the colour are in proportion to the extent of the 

 lignification. 



CHLORIDE OF ANILINE. 



Chloride of Aniline, 2 grms. ; Rectified Spirit, 65 cc. ; Dis- 

 tilled Water, 35 cc. ; Strong Hydrochloric Acid, 2 cc. 



Sections containing lignified tissue placed in this solution 

 for 15 to 30 minutes are stained a yellow colour, but the 

 differentiation is not so good as with Phloroglucin. 



