The protoscolices and free cysts of Echinococcus multilocularis were incubated for ten days in three kinds of media to which different kinds of the drugs were added at the rates of 10,40 and 100 γ per ml. The main medium, which consists essentially of medium 199 with calf serum in proportion of 20 per cent, was used for the drugs soluble in water. Most drugs insoluble or slightly soluble in water were added to the main medium as a solution in 2 mg per ml of propylene glycol. To observe the effect of propylene glycol, the scolicidal effect of bunamidine hydrochloride suspended in the medium containing 0.3% methylcellulose were compared with that in the medium with propylene glycol. The survival rates of protoscolices and free cysts with each drug were compared to each other together with those tested in the preceding report (SAKAMOTO et al., 1965). The derivatives of halogenized salicylanilide manifested the highest scolicidal effect, and the derivatives of halogenized bisphenol ranked next. Bunamidine hydrochloride and cyanine dyes gave a comparatively high scolicidal effect. The intensity of scolicidal action in halogenized derivatives of salicylanilide and bisphenol increased with the increase of the number of halogen atoms, such as chlorine and bromine, in their phenol rings. The presence of propylene glycol in the medium shows a tendency to increase the intensity of scolicidal action of drugs insoluble in water
