Botkin's Apparatus

BOTKIN'S APPARATUS for the cultivation of anaerobes, is adapted for replacing the air, respectively oxygen, with some indifferent gas, for example, hydrogen or nitrogen. This apparatus consists of a large evaporating dish A, into which a glass bell jar B is inserted.

To prevent the edges of the bell jar from coming into tight contact with the bottom of the dish, a metal (lead) cross is placed beneath them of such a thickness that there is a gap of 2-3 cm between the edges of the bell jar and the bottom of the dish. This gap is necessary so that two gas tubes can be led into the interior of the bell jar: the inlet tube C, which is longer and reaches up to the dome of the bell jar, and the outlet tube D, which terminates in its lower part. Inside the bell jar, there is a stand E for Petri dishes or test tubes. An alkaline solution of pyrogallol is placed on the lower part of the stand to absorb oxygen.

When using the apparatus, the procedure is as follows. Some indifferent liquid that poorly absorbs oxygen, liquid paraffin, or mercury is poured onto the bottom of the evaporating dish; then the stand with inoculated Petri dishes or test tubes is placed inside. Pyrogallol is added to the lower small dish containing a 50% alkali solution, and it is quickly covered with the bell jar, having previously introduced the gas tubes, while a weight in the form of a metal ring is placed on top of the bell jar so that the bell jar does not accidentally overturn. Hydrogen from a Kipp's apparatus is passed through the inlet tube until the air is completely displaced, which is recognized by the absence of an explosion when the gas escaping from the outlet tube is ignited. The apparatus assembled in this manner is placed in an incubator. The apparatus is convenient because it can be easily constructed. The evaporating dish can be replaced by a metal basin, and the bell jar by a large bottle with the bottom knocked off; its neck is tightly plugged with a rubber stopper.

A. Chelny