Fig. 254.—Pasteur’s Bulb Pipette.
Fig. 255.—Storing Cultivation Tube.
Sternberg advocates the use of a glass bulb, provided with a slender neck drawn out to a fine point and hermetically sealed. Special forms of tubes, bulbs, and pipettes were devised by Pasteur, and are still in use at the Bacteriological Institute, Paris, and known as the Pasteur’s bulb pipette ([Fig. 254]).
Others are provided with lateral or with curved arms, one of which is drawn out to a fine point, and the slender neck plugged with cotton-wool, as in [Fig. 255].
THE WARM CHAMBER, STERILISER, AND INCUBATOR.
Fig. 256.—Pfeiffer’s Warm Chamber.
The Warm Chamber.—This is an accessory of importance in bacteriological work. For the continuous heating of specimens during cultivation it is an absolute necessity. Pfeiffer’s warm chamber ([Fig. 256]) is suitable for microscopical work generally. It consists of a hard-wood box, made air-tight, with doors and glass windows to allow of the specimen being moved from time to time, and kept under constant observation. The box is mounted on a metal plate tripod stand, and is heated from below by a small gas burner, with a thermo-regulator. A paraffin lamp will do as well, so long as it maintains a temperature of from 25° to 45°C., and without danger of injury to the stand and lenses of the microscope. A thermometer is placed in the air space to mark the temperature.
