140 



BOTANICAL GAZETTE 



[febru.\ry 



nitrogen in diseased bark may be due to fixation by the fungus 

 or to a withdrawal of nitrogen from the surrounding tissue. Fur- 

 ther data are necessary before a conclusion can be reached. Cul- 

 pepper, Foster, and Caldwell found protein-nitrogen content 

 of fraction 2 for diseased apples larger than for normal ones, but 

 the total nitrogen for the whole tissue smaller for the former than 



for the latter. 



TABLE XXV 



Summary 



Results with healthy samples 3 and 4 furnish Httle of additional 

 interest. They show, however, that as far as total nitrogen and 

 starch are concerned, the small amount of wood in the other 2 

 healthy samples had no effect on the results. The difference in 

 the case of dry weight and reducing sugars before and after hy- 

 drolysis is probably due to the fact that samples 3 and 4 were taken 

 from a Hmb cut early in the growing season, while samples i and 2 

 were taken from limbs cut in the dead of winter. 



Estimation of tannin 



The method used was that of Lowenthal, as modified by 

 Proctor (34, p. 150). Material for analysis was taken from 

 8-12 cm. Ben Davis limbs cut in November, December, and 

 January. The bark was cut off as already described, ground in a 

 meat grinder, and transferred to a glass moist chamber at once. 

 About 10 gm. were then weighed out and set to boil in 400 cc. of 



