Apparatus, Material, and Reagents employed in Bacteriological Investigations.
A good microscope with a wide-angled sub-stage condenser, and objectives of an inch, ¼-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.
 Fig. 246.—Pipettefor Micro-chemicalFiltration. |  Fig. 247.—Bottle andDipper for CedarOil. |  Fig. 249.—Needle Holders,fine Lifter and Hook forManipulating Structure. |
 Fig. 248.—Box forkeeping Glass-covers. | ||
 Fig. 250.—Section Lifters. |  Fig. 251.—SpringFlat Forceps. |  Fig. 251a.—Forcepswith 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).
Collapsible tubes for containing Canada balsam and dammar.
Soft rags or old pocket handkerchiefs for removing cedar oil from lenses and cover-glasses. Chamois leather for wiping lenses and removing dust.
Reagents, alcohol, bergamot oil, celloidin, dissolved in equal parts of ether and alcohol.
Ebner’s solution. (See Appendix.)
Formalin, glycerine, gelatine, Klebs’ and Kleinenberg’s solutions. (See Appendix.) The latter consisting of a watery solution of picric acid 100 parts; strong sulphuric acid two parts; filter, and add distilled water 300 parts.
Muller fluid. (See Appendix.)
Osmic acid, a five per cent. solution.
Paraffin, spermaceti and xylol, acetic acid, hydrochloric acid, a one per cent. solution with alcohol.
Ammonia liquid, ether, picro-lithium carmine, potash solution.
Safranine, concentrated alcoholic solution of, and a watery solution.
Turpentine, vesuvin, water distilled and sterilised.
Aqueous solutions of the several dyes may be kept in bottles ready for use.
To both aqueous and alcoholic solutions a few drops of phenol, or a crystal of thymol, should be added as a preservative. For the rapid staining of cover-glass preparations, it is convenient to have the most frequently used stains—fuchsine, methyl-violet, &c.—in bottles provided with pipette stoppers.
Clearing Agents.—Oils of cedar wood, cloves, origanum, aniline, terebene, toluol and xylol, benzol and spirits of turpentine.
Mounting Media.—Acetate of potash solution concentrated, benzole, balsam, glycerine jelly, Fanant’s medium, dammar and mastic, Canada balsam in xylol, Hollis’s glue, zinc white.
Cement for fixing small specimens temporarily to a glass slide. Remove all traces of moisture, place upon it a drop or two of a medium prepared as follows:—Dissolve over a water bath 15 grammes of white lac in 100 grammes of absolute alcohol, decant off the clear liquid, and stand it by for a while.
As the alcohol evaporates from the warmed surface of the glass slide a hard transparent coating is left. This may be slightly softened at any time by means of a drop of oil of lavender. After arranging the objects the heat of a spirit-lamp will cause the oil to evaporate, leaving them firmly attached. Objects may be mounted on cover-glasses in a similar way. A resinous mounting medium may then be employed in the usual manner. If glycerine or glycerine jelly is the mounting medium employed, collodion diluted with two or three times its volume of oil of lavender may be found preferable as the fixing agent. The section should be placed in position before the preparation dries and the oil is evaporated.
Methylated spirit is often so largely adulterated with rock-oil as to render it unsuitable for technical purposes. Even to varnishes it imparts a fluorescent appearance as it dries off.
Fig. 252.—Iron Box for holding Sterilised Instruments and Glass Plates.
The needles and instruments used must not be passed through a Bunsen burner flame, which is most destructive, but enclosed in a sheet-iron box made for the purpose ([Fig. 252]), and placed in the hot-air steriliser for an hour at 150°C. The box can be opened at the side, and each instrument withdrawn with a pair of sterilised forceps when required for use.
Glass plates are sterilised in the same iron box, and the platinum needles for inoculating nutrient media, examining cultivations, &c., are served in the same manner before being used. The needles consist of two or three inches of platinum wire fixed to the end of a glass rod. Several of these needles should be made by fixing pieces of wire into a glass rod about six inches long. The glass rod must be heated at the extreme end in the flame of a Bunsen burner, or blow-pipe, and the platinum wire held near one extremity with forceps, and fused into the end of the glass rod. Some of these rods should be straight, and some bent, and others provided with a loop, and kept especially ready for inoculating test-tubes of nutrient jelly.
Fig. 253.—Damp Chamber for Plate-cultivations.
Glass Dishes.—Several shallow glass dishes are required for preparing damp chamber cultivations, the upper covers fitting over the under (as in [Fig. 253]), in the centre of which culture-plates are stacked one above the other, and when necessary placed in the incubator.