Abstract
In accordance with the facts that some acaroid mites have been reported to breed in certain drug samples in Japan, experiments were made to know the rates of breeding of Tyrophagus dimidiatus in 120 kinds of drugs. Three gramms of each sample was placed in inner vial of a double glass chamber, to which about 300 mites were released and saturated KCl solution was put into the outer vial to regulate the relative humidity at 85%. The vials were kept in an incubator at 25℃, and the number of mites per 0.5gm. of the sample as well as thier rates of survival was observed at the interval of two weeks until the fifteenth week. The results may be summarized as follows. A. Drugs in which remarkable reproduction of more than 500 mites per 0.5gm. was observed are most of the enzyme and protein samples. B. Drugs in which slight reproduction was observed are some of the above kinds of drugs and some tablets and powder drugs containing starch or lactose. C. Drugs in which no reproduction occurred but the survival of placed mites was observed more than two weeks are : most inorganic and organic compounds with no miticidal actions. D. Drugs in which prompt death of the mites was observed are some organic or inorganic compounds presumably with miticidal effects.
