302 ON A NEW CANKER-DISEASE OF PRUNUS YEDOENSIS, etc. 
on the dead twig for a long time (PI. VIII, Fig. 3.). But the lower branches 
were still in foliage up to the end of September, although the diseased area 
had slowly been extending. 
Experiments VI. 
From January to April, 191 5, I several times tried various kinds of 
inoculation on the three-year seedlings of P. yedoensis and also the com- 
paratively old potted trees of a kind of P. serrulata. And the conclusion 
was reached that this fungus most easily infects the hosts at the old wounds 
which have a layer of dead cells on the exposed surface. In these exoeri- 
ments the pots were placed under bell-glass in order to keep them moist for a 
week. The details of these experiments are shown in the following table : — 
Table XIII. 
Inoculated portion 
Time of 
inoculation 
Inoculum 
Results 
I. Sound buds of seedling 
Jan. 26 
Pycnospores from culture 
— but infected 
buds wilted 
2. New slit wounds on seedling 
Jan. 26 
Ascospores from natural host 
3. Older wounds on seedling 
March 13 
Mycelium from culture 
+ 
New slit wounds on aged 
4. 1 
potted tree 
Febr. 12 
Mycelium from culture 
Burnt portion on aged potted 
- 1 ' tree 
Febr. 12 
Pycnospores from culture — 
g Burnt portion on aged potted 
tree 
April 16 
Pycnospores from culture | + 
In the first case, it seemed to me that the germ-tubes of the inoculated 
spores had the power to kill the buds. But on the sound bark, the infection 
never took place. In the third case, four slit wounds were given with a steri- 
lized scalpel on the bark of the three-year-old seedlings, about two months 
before inoculation. On March 13th, 191 5, mycelium with a little piece of the 
cultural medium was inoculated in the upper three wounds, and the lowest 
wound was treated as a check. About the 9th of April, the upper-most 
shoot wilted, and at the end of the same month the second shoot wilted, 
developing at the same time many small pustules of the young stage of the 
