Notes on Technic

Abstract

Recently in the Parasite Laboratory at Roanoke College it became necessary to work with digenetic trematodes fixed and stored in Gilson's fluid for more than a year. When starting with fresh parasites, Siddiqi and Cable (1 960) employed a sublimate-acetic fixative if immediate processing was possible. They washed the specimens, dehydrated to 70% ethanol and treated them with an alcoholic 1,KI solution to remove mercurial precipitates. Another technique for removing precipitates (Galigher and Kozloff 1964) requires dropwise addition of an I,KI solution to one of the dehydrating alcohols containing the specimens. Both these methods were quite inadequate for our purpose because much precipitate remained even after the worms had been strongly colored by iodine.We suspected that the concentration of iodine was too low in the customary procedures to react with all the precipitate which had accumulated during gross overfixation of more than a year in Gilson's fluid; therefore, we used an 1,KI solution which contained 5% iodine. The technique which restored nearly all of the overfixed specimens to usefulness for taxonomic studies is as follows: Procedure 1. Soak the specimens in 70% ethanol for about 48 hr, changing the fluid at 12-16 hr intervals.