Botkin Apparatus

Botkin Apparatus, for the cultivation of anaerobes, is adapted to replace air, resp. O, with some indifferent gas, e.g., N or N. 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 fitting tightly against the bottom of the dish, a metal (lead) cross is placed underneath it, of such 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 tubes can be introduced inside the bell jar: the gas-inlet tube C, which is longer and reaches the dome of the bell jar, and the gas-outlet tube D, which ends in its lower part. Inside the bell jar is placed a stand E for Petri dishes or test tubes. On the lower part of the stand is placed an alkaline pyrogallol solution for absorbing O. When using the apparatus, the following procedure is followed. Some indifferent, poorly absorbing O, liquid, liquid paraffin, or Hg is poured into the bottom of the evaporating dish; then the stand with the seeded Petri dishes or test tubes is placed. To the small dish containing the 50% alkali solution, pyrogallol is added, and the bell jar is quickly covered, having previously connected the gas tubes, and a weight in the form of a metal circle is placed on top of the bell jar so that it does not accidentally tip over. Through the inlet tube, N from the Kipp apparatus is passed until the air is completely displaced, which is recognized by the absence of an explosion when the gas flowing from the outlet tube is ignited. The assembled apparatus is placed in a thermostat. 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 its bottom knocked out; its neck is tightly plugged with a rubber stopper.