276 ON A NEW CANKER-DISEASE OF PRUNUS YEDOENSIS, etc. 
four months, the spores have not been observed in those stromata. 
(7) Bean Agar Slant. 
On this medium the growth of the mycelium is very slow, and causes no 
darkening of the medium. But the mycelial grow th is more or less thick, 
and after six months some of the tubes produced the stromata and pycno- 
spores. The color of the mycelium is at first snow-white, but gradually 
turns to a very light yellow color. 
(8) Soy Agar after Miyoshi. 
The use of Japanese soy as a cultural medium of the fungi was at first 
proposed by Dr. M. MiYOSHI. The formula, which I used in this study, is 
as follows : — 
Soy 20 c. c. Cone, boiled onion juice 25 c. c. 
Cane sugar 5 gr. Dist. water 50 c. c. 
Agar 1.5 % 
On this medium the growth of both aerial and creeping mycelium is very 
vigorous, covering the whole surface of the medium with a very thick hyplial 
layer, and its entanglement is more or less close. But both stromata and 
spores are not produced, and the color of the mycelium is at first white and 
then gradually turns into very light yellow or gray. 
(9) Potato Agar. 
This medium was also used as the standard medium of the tannic acid 
cultures. Cultures containing no tannic acid or citric acid showed a very 
poor growth of the fungus, lacking the aerial mycelium, and producing no 
stromata and spores. The growth of the fungus caused no darkening of the 
medium. Cultures containing low percentages of such acids showed more 
or less good results as the cultural media and about them I shall explain in 
detail in the following chapter. Although the color of the mycelium was 
white on slants in test tubes, containing no such acids, the plain cultures of 
