亞砒酸及びSpirocidの培養赤痢-Amoebaに及ぼす作用

抄録

Numbers of clinicians have already applied various arsenous preparations in the treatment of amoebic dysentery with very various therapeutic results, but there are few who have tried any experiments dealing with their direct effects upon dysentery amoebas. In order to discover the degree of difference between arsenous preparations and other drugs, I observed the effects of arsenous acid and spirocid upon dysentery amoebas in culture. Moreover, I cultivated many generations of dysentery amoebas successively in culture media containing arsenous acid, and by this method I was able to observe whether or to what extent dysentery amoebas can become accustomed to the drug. The main results of my experiments are as follow : 1) By the method of examining amoebas on the objectglass, even in solutions containing 1 % of arsenous acid, most of the vegetative and minute forms of dysentery amoebas remain apparently unharmed for 4 hours. 2) By the method of cultivating 5 generations of amoebas successively in culture media containing arsenous acid, the development of the vegetative forms was disturbed in culture media containing of 0.0001-0.00001 % of the drug, but the disturbance in the development of the minute forms took place in the concentration of 0.01 % 3) By the method of examining amoebas on the objectglass, in a solution containing 1.0 % of spirocid, a considerable proportion of the vegetative forms died within 55-85 minutes, but most of the minute forms showed scarcely any change. In a 0.1 % solution, even the vegetative forms remained apparently unharmed for 4 hours. 4) By the method of cultivating 5 generations of amoebas successively in culture media containing spirocid, in a concentration of 0.1 %, the development of the vegetative forms was disturbed, but the minute forms continued their development well. 5) The vegetative forms were successively cultivated in culture media containing 0.0000001 %, 0.000001 % or 0.00001 % of arsenous acid. In the concentration of 0.0000001 % the vegetative forms continued their lively development for 30 generations, but in the concentrations of 0.000001 % or 0.00001 %, their development declined gradually, and died off between the 9 th-12 th generations. In order to ascertain whether they acquire a better tolerance of the drug, part of the vegetative forms were cultivated in culture media containing 0.0001 % of arsenous acid in the 10 th, 20 th and 30 th generations, but there was no difference between their development and that of controls. 6) The vegetative forms were cultivated in culture media containing 0.0000001 %, 0.000001 % or 0.00001 % of arsenous acid, and the concentration of the drug was increased by degrees. They developed well at the outset, but later their development gradually diminished, and when the concentration was raised to 0.00009 %, all of them died off. In this concentration the normal vegetative forms at times also developed. 7) The minute forms were successively cultivated in culture media containing 0.001 % of arsenous acid for 30 generations, and part of them was cultivated in culture media containing 0.1 % of the drug in the 10 th, 20 th and 30 th generations, but there was no difference in development between them and the controls. 8) The minute forms were cultivated in culture media containing 0.01 % of arsenous acid, and the concentration of the drug was increased by degrees. Their development was found to continued until the concentration was raised to 0.02-0.06 %, but upon the concentration being still further increased, they died off. In these concentrations-the normal minute forms could develep for a few generations. 9) The results of the experiments I have described above indicate that arsenous acid has a far stronger effect upon the vegetative forms of dysentery amoebas than hydrochloric emetin, but that the effect of the two drugs upon the minute forms is almost equal.