1922] WILLAMAN & SANDSTROM—SCLEROTINIA 291 
in healthy parts. The amount of nitrites was proportional to the 
intensity of the pathologic condition. The reducing organisms 
were mostly in the vascular tissues. The reduction of the nitrates 
brought about nitrogen starvation, with a consequent yellowing 
and distortion of the affected tissue. In a field where potatoes had 
been grown continuously for fifteen years, nearly every vine was 
affected with nitrogen starvation, although the soil contained an 
abundance of nitrates. In tobacco mosaic it was observable that 
the plants tended to oppose these chemical forces both by morpho- 
logical and by physiological means; thus the secondary organs were 
reduced in size, more water was transpired, and the oxidizing — 
enzymes showed greater activity. 
Jopip1, Mouton, and Mark ey (34) made a detailed dissec- 
tion of the nitrogen constituents of spinach mosaic, and found 
evidences of denitrification, due to the production of nitrites and 
their subsequent action on amino nitrogen groups. In cabbage 
mosaic (33) a similar condition was found, hence nitrogen starva- 
tion is believed to be the cause of the abnormal appearance of the 
leaves in these diseases. It is to be regretted that Boncquet and 
BoncQvueEt give none of their methods of analysis, nor any data 
whatsoever in their papers. 
Material 
Five varieties of plums, grown at the University Fruit Breeding 
Farm at Excelsior in 1920,? were selected for the work. Three of 
them show marked resistance to the attacks of the brown rot fungus, 
while the other two are very susceptible. Samples were picked at 
three stages of growth: (1) when half grown, (2) when fully grown 
and just beginning to ripen, and (3) when fully ripe, but still on 
the tree. In most cases each sample was divided into three por- 
tions. One portion was analyzed immediately, another was inocu- 
lated with a pure strain of Sclerotinia cinerea and placed in a moist 
chamber to rot, and a third portion was placed in a moist chamber 
without inoculating and left for the same length of time as the 
Corresponding inoculated portion. The inoculations were made by 
injecting a suspension of spores with a hypodermic syringe into the 
? Acknowledgments are due to Dr. M. J. Dorsey for assistance in obtaining the 
terial. 
