Atkins — Ox/jdascs and their Inhibitors in Plant Tissues. 161 



be mentioned that exposure to the reagents without the addition of hydrogen 

 peroxide only resulted in a slight browning of the epidermis in one instance 

 {I. X/phhmi, var. Battandieri, blanche superbe) after an exposure of forty 

 minutes, whereas ten minutes after the addition a well-marked reaction Iiad 

 appeared in the veins and epidermis of a number of varieties. 



An attempt at a colorimetrio quantitative estimation is indicated by the 

 number of plus signs. The chemistry of these changes is dealt with by 

 Keeble, Armstrong, and Jones (8). 



Table II shows the result of the application of the above two artificial 

 chromogens after treatment of the perianth leaves with 0'2 per cent, 

 hydrogen cyanide, and subsequent thorough washing. For this purpose 

 leaves from the flower employed in the experiment of Table I were made 

 use of in each case, the two treatments being carried on concurrently. 



For convenience of reference the specimens are numbered consecutively 

 through the various tables. 



Table I. 



Xiphion Group. 



