EFFECTS ON INVERTEBRATES 



577 



tensively inactivated in serum. Tests in mice infected with Schistosoma 

 showed that menadione, the most effective quinone, has relatively little 

 effect by itself, but can potentiate the action of stibojjhen (Fuadin) in 

 promoting migration of the organisms from the veins to the liver. Several 

 quinones are cercaricidal at concentrations of 0.2-0.5 mM, but the data 

 are too inaccurate to assign relative potencies (Schreiber and Schubert, 

 1949). It is likely that the cidal mechanism is entirely different from the 



Fig. 5-10. Effects of toluquinone on planaria. Closed circles — le- 

 thal time; open circles — tail end disintegration time; closed tri- 

 angles — head end disintegration time. (From Schreier, 1949.) 



suppressive or antiglycolytic actions studied by Bueding and his co-workers. 

 Intestinal Trichinella spiralis infections in rats were treated with menadione 

 (most other benzo- and naphthoquinones were shown to be ineffective) 

 by Oliver-Gonzalez and Bueding (1948), and it was shown that oral ad- 

 ministration leads to 81% reduction in the number of adult trichinae in 

 the intestine. There is no correlation between the actions of the quinones 

 on Schistosoma and Trichinella and the mechanisms appear to be different, 

 according to Bueding. 



