A modified eosin technique similar to that used for differential staining of live and dead spermatozoa stained dead cercariae of Schistosoma mattheei red while those that were alive remained colourless and transparent.
Prior to exposure to the dye live cercariae were immobilized with physostigmin, which was better for that purpose than five other substances tested.
The lowest concentration of physostigmin to immobilize cercariae quickly and effectively was found to be 3,3 x 10-⁶ M.
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