METHODS OF ANAEROBIC CULTIVATION. 



6l 



Fig. 



-r\o\'}'s anaerobic jar. 



minutes before closing the coclc in the top of the jar. In effect- 

 ing displacement of the air it is necessary to observe to adjust 

 the cock so that the gas enters directly 

 into the jar from above and finds its 

 way out through the combined rub- 

 ber and glass tubing adjustment from 

 below. 



In the alternative method, use is 

 made of an ordinary chemical desic- 

 cating jar of suitable size, 6 inches in 

 diameter, in the lower compartment of 

 which is placed about 150 c.c. of a i 

 per cent sodium hydrate solution in 

 which is dissolved 10 grammes of 

 pyrogallic acid. Into the upper portion of the jar are placed 

 the Petri's dish cultures, and at once the cover of the vessel, pre- 

 viousl}^ smeared with vaseline on its contact surface, is firmly 

 affixed. These vessels are then placed for forty-eight hours in 

 the thermostat before examining. 



(c) By Bulloch' s Apparatus for Anaerobic Culture. — This can 

 be recommended for plating out mixtures containing anaerobes, 



and for obtaining growths (especially 

 surface growths) of the latter. It 

 consists (Fig. 26) of a glass plate as 

 base on which a bell-jar can be firmly 

 luted down with unguentum resinas. 

 In the upper part of the bell-jar are 

 two apertures furnished with ground 

 stoppers, and through each of the lat- 

 ter passes a glass tube on which is a 

 stopcock. One tube, bent slightly 

 just after passing through the stopper, 

 extends nearly to the bottom of the 

 chamber ; the other terminates imme- 

 diately below the stopper. In using 

 the apparatus there is set on the base- 

 plate a shallow dish, of slightly less diameter than that of the bell- 

 jar, and having a little heap of from two to four grammes of dry 

 pyrogallic acid placed in it towards one side. Culture plates 

 made in the usual way can be stacked on a frame of glass rods 



Fig. 26. — Bullocli's apparatus for 

 anaerobic plate-cultures. 



