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ON A NEW CANKER-DISEASE OF PRUNUS YEDOENSIS. etc. 
11. Resistant Power of the Hyphae against Solutions of 
Corrosive Sublimate, Copper Sulphate, and other Chemicals. 
Solutions of corrosive sublimate and copper sulphate are generally used 
for fungicides, and occasionally soda-solutions are used for the same purpose 
in our country. When surgical operations of various canker-diseases are 
performed, they are also used to wash the exposed surface of the wound. In 
order to determine first their killing power against the hyphae of the present 
fungus, I poured each of these poisonous solutions into a test-tube, in which 
the hyphae had been growing up actively. After certain intervals, as indi- 
cated in the following tables, I took out the pieces of hyphae with a platinum 
needle, and washed them in distilled water which had been previously steri- 
lized, and again inoculated on a new cultural medium. 
Of course such experiments are not precise, because the chemicals can 
not sometimes touch the hyphae, owing to the air layer which is surrounding 
them. It was most conspicuous in the case of copper sulphate. Even if the 
results of my experiments were not conclusive, for the one purpose of deter- 
mining thejr value as fungicides, we can safely summarize as follows: — 
1. Corrosive sublimate has a strong sterilizing power for the hyphae of the 
present fungus, being effective even in such a dilute solution as 0.01 %. 
But as a fungicide, it is safer to use a 0.05 % or O- 1 °/o solution. 
2. Copper sulphate and carbonate of soda did not give good results for the 
same purpose, probably .owing to the disturbance of the air layer. 
3. Caustic soda has sterilizing power for the hyphae of the present fungus, 
when such a concentrated solution as iO°/ 0 or 2O°/ 0 is used. Even with 
the 5.0% solution, we can probably obtain good results for the same pur- 
pose. 
The results of these experiments are given in the following tables. In 
these tables the plus sign means the presence of the living hyphae and the 
minus sign means their death. 
