400 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
2 parts paraffin and 1 part caoutcliouc. When the medium is cold it is 
inoculated by means of a freshly made capillary tube and introduced 
through the short tube b, after which the latter is at once sealed up. In 
order to collect the gases formed, the end of the tube a is immersed in 
mercury and covered with a eudiometer. 
By the foregoing arrangement only a moderate amount of oxygen 
remains in the flask, and this is soon expelled or replaced by the fer- 
mentation gases. If it be de- 
sirable to fill the apparatus 
with hydrogen for anaerobic 
cultivation, all that is neces- 
sary is to connect the a end 
with a hydrogen-forming ap- 
paratus directly after sterili- 
zation while everything is 
hot, for as the apparatus 
cools down it gets filled with 
hydrogen. 
It is sometimes necessary 
to supply air to cultivations, 
and this may be done by the 
arrangement shown in fig. 57. 
In this stopper are three holes, two of which are fitted as in fig. 56, while 
the third hole is for the passage of a U-tube, one leg of which reaches 
nearly to the bottom of the flask and is drawn out to a point ; on the 
other end are two bulbs filled with some antiseptic fluid. The air is 
better forced in at c than sucked in at a. For this purpose a couple of 
Fig. 56. 
Fig. 57. 
large flasks are placed in connection with each other and the tube c ; 
one flask, placed higher than the other and containing water, forces by the 
fall of the water the air from the second flask through the tube c. When 
one flask is empty the positions are reversed. 
