Bacteria Cultivation, Sterilising, and Preparing for Microscopical Examination. That branch of mycology which is now looked upon as a separate department of science, termed bacteriology, took shape in the years 1875-9, when its founder, the veteran botanist Cohn, who recognised that the protoplasm of plants corresponded to the animal sarcode, published his exact mode of studying bacteria. But it was a pupil of his, Dr. Koch, who a year later discovered that a specific cattle disease, anthrax, was due to a bacillus, and it was he also who gave us the useful modification of gelatine as a medium in which to grow bacteria; he hit upon the method of pouring melted gelatine containing distributed germs on to plates, and thus isolating the colonies and ensuring the further isolation of the spores, and so facilitate the preparation of pure cultures on a large scale, and with great saving of time. The difficulty of isolating a bacterium and tracing its life history under the microscope must at first sight appear great. A further objection that such work is slow and difficult has no more weight here than in any other department of science, as will be seen on proceeding to follow out the directions I am about to furnish for the use of the student. Apparatus, Material, and Reagents employed in Bacteriological Investigations. A good microscope with a wide-angled sub-stage condenser, and objectives of an inch, 1/4-inch, or 1/6-inch, and a 1/12-inch homogeneous oil-immersion. A large bell-glass for covering the same when fuming acids are in use in the laboratory. About a square foot of blackened plate-glass. A white porcelain slab, or a shallow photographic dish of some size. Glass bottles with ground stoppers for alcoholic solutions and aniline dyes. Glass bottles with funnels for filtering solutions of stains, with pipettes. A specialised form of pipette for the micro-chemical filtration of solutions (Fig. 246). A small stoppered bottle of cedar oil (Fig. 247). Set of small glass dishes or watch-glasses for section staining. Stock of glass slides sterilised, together with round thin glass-covers, in boxes (Fig. 248). Needle holders and platinum needles, with a packet of ordinary sewing needles (Fig. 249). Platinum, or plated copper section-lifters (Fig. 250). Glass rods, drawn out to a fine point, for manipulating sections when acids are employed. [Illustration: Fig. 247.--Bottle and Dipper for Cedar Oil.] [Illustration: Fig. 246.--Pipette for Micro-chemical Filtration.] [Illustration: Fig. 248.--Box for keeping Glass-covers.] [Illustration: Fig. 249.--Needle Holders, fine Lifter and Hook for Manipulating Structure.] [Illustration: Fig. 250.--Section Lifters.] [Illustration: Fig. 251.--Spring Flat Forceps.] [Illustration: Fig. 251_a_.--Forceps with fine Points.] A pair of small spring steel platinum-pointed forceps for holding glass-covers (Fig. 251). One or two pairs of fine-pointed forceps (Fig. 251_a_).