ANTHRAX. 359 fuchsin, the bacilli decolorized with a very weak acid and then counter-stained with a watery solution of methyl blue. . Upon the surface of gelatin plate-cultures the bacillus forms beautiful and highly characteristic colonies (Fig. 103). To the naked eye they appear first as minute FIG. 103.—Bacillus antliracis: colony upon a gelatin plate; x 100 (Frankel and Pfeiffer). round whitish dots occurring upon the surface, and caus- ing liquefaction of the gelatin as they increase in size. Under the microscope they can be seen in the gelatin as egg-shaped, slightly brownish granular bodies, not attain- ing their full development except upon the surface, where they spread out into flat, irregular, transparent growths bearing a partial resemblance to tufts of curled wool. From a tangled centre large numbers of curls extend, each made tip of parallel threads of bacilli. As soon as the colony attains any considerable size liquefaction be- gins. These colonies make beautiful adhesive prepara- tions. If a perfectly clean cover-glass be passed once through a flame and laid carefully upon the gelatin, the colonies can generally be picked up entire when the glass is removed. Such a specimen can be dried, fixed, and stained in the same manner as an ordinary cover-glass preparation.