136 



BOTANICAL GAZETTE 



[FEBRUARY 



the whole section. Catalase, judging by evolution of gas when 

 H2O2 was added, was evenly distributed in all the tissues. Tests 

 with FeCl3 on sections of bark successively farther and farther 



TABLE XXII 



REStTLTS OF MICROCHEMICAL TESTS ON HEALTHY AND DISEASED BARK 



distant from the badly browned region showed steadily increasing 

 amounts of tannin. Pectin seemed to be present in about equal 

 amounts in both healthy and diseased tissues. 



Macrochemical analysis 



Six samples were analyzed. The analytical methods used for 

 4 of them are based on those^employed by Koch for the quantitative 

 study of animal and plant tissues (21, pp. 199-207). The differ- 

 ence in material required minor variations from these methods, 

 but it is not thought necessary to describe them here. The other 



