Materials and Methods

Methods used in this study are essentially those outlined elsewhere (Bary, in press). Mass cultures were allowed to develop in the field sample, or, where subcultures were required, in hay infusions. Pure-line cultures were not used. Generally, Yocom's (1918) or Gray's (1932) techniques were followed. These are rapid methods for preparing whole mounts of specimens, which are killed and fastened to the slide by prepared fluids and then stained. Hot Schaudinn's or hot Bouin's proved satisfactory fixatives. Sections of Glaucoma were stained with iron haematoxylin, and very satisfactory pellicular and cytostomal preparations were obtained with 10 per cent, nigrosin solution (Coles, 1927). Ehrlich's haematoxylin, counter-stained with eosin, gave clear differentiation of the nuclear complex. In Stentor species it was not possible to prevent contraction on killing, nor to use nigrosin, as specimens disintegrated under its influence.