286 
ON A NEW CANKER-DISEASE OF PRUNUS YEDOENSIS, etc. 
Per cent 
of 
Growth of Mycelium 
Production of 
pyenospores 
Grade 
Remarks 
No tannin 
+ + 
loose 
O.I 
+ + 
close 
+ + 
0.4 
+ + + 
closest 
+ 
0.7 
+ or — 
close 
1.0 
- 
Experiment III. 
In this experiment the same media and methods were used as in the case 
of the second experiment. It was started at the beginning of May, 1915. In 
this case, Valsa Mali and Valsa Paulozvniae were taken up in addition to the 
causal fungus, for the sake of comparison. The results are given in the 
following table. 
Table IV. 
Shoiving the effect of the different percentages of tannic acid in the standard 
medium on the groivth of the causal fungus and tivo other species of Valsa. 
1 Per cent, 
of 
tannic acid 
The causal fungus 
Valsa Mali 
Valsa Paulowniae 
Growth 
Production 
of pyenospores 
Growth 
Production 
of pyenospores 
Growth 
Production 
of pyenospores 
No tannin 
+ + 
+ + 
+ + + 
O.I 
+ + 
+ 
+ + 
+ 
0.4 
+ + 
+ 
+ or — 
0.7 
+ or — 
| 1.0 
_ 
c. Conclusion. 
From the foregoing experiments on the effect of tannic acid on the de- 
velopment of the causal fungus and other species of Valsa, the following con- 
clusions may be drawn : — 
