The group marked B, Fig. 1, and dots inside A, are microscopical objects of minutest form and simplicity of structure. They are protoplasmic, or bioplasmic, automobile, capable of arranging themselves into varied forms and shapes, and reproducing themselves by division into countless hosts.

D, K, saprolegnias, are two figures of saprolegnia found in Croton-water. Similar ones are also found growing parasitically on the bodies of dead flies lying in water, fish, frogs, and in some cases, on decaying plants. To the naked eye they appear like colorless, minutely filamentous tufts adherent to such objects, forming a kind of gelatinous cloud, more or less enveloping them. Under the microscope the tufts are seen to consist of long, colorless, tubular filaments, spreading out in all directions, with or without branches.