124 



BOTANICAL GAZETTE 



[FEBRUARY 



BuNZELL (9, 13) with tuKp tree leaves and with potatoes, although 

 the mean value of k in all 3 cases is much larger than that found for 

 bark. Attention has already been called to the fact that the data 

 in table XIV, column i (also from Bunzell's work), fail to fit the 

 equation for a unimolecular reaction. The fact of a marked rise 



TABLE XIII 



Values of k calculated from data published by 



BUNZELL (9) FOR POTATO JUICE 

 AND PYROGALLOL 



/ (min) 



10. 

 20. 

 30. 

 40. 

 50. 

 60. 

 70. 

 80. 

 90. 



Mean. 



k* 



0.0262 



/ (min) 



Mean . 



kf 



0.0246 

 0.0277 

 0.0199 

 0.0168 

 0.0174 

 0.0233 



0.0208 



* 23i p. 29. table VII, columns i and 4. 

 t 23, p. 26, table II, columns 5 and 7. 



TABLE XIV 

 Values of k calculated from data published by Bunzell (13) 



in the value of k toward the end of the experiments with bark may 

 mean that at that point the "oxidase" oxidizes not constant frac- 

 tions but constant weights of pyrogallol in a given time (Philip 27, 

 p. 295). The data at hand, however, are insufficient for a veri- 

 fication of this hypothesis. 



