1910. | Oxidation of Phenol by Certain Bacteria. 153 
Flask Experiments.—Similar experiments to the preceding were made with 
cultures of the chromogenic organism under rigid sterile conditions. Four 
flasks (300 c.c. capacity), fitted with rubber stoppers, tubes, etc., and con- 
nected in series, were used in each experiment. The inlet of the first 
flask and the outlet tube of the fourth flask were connected with wide 
tubes drawn out at one end and plugged with cotton wool. 
To each of the four flasks at the outset of experiment was added 150 c.c. 
of phenol solution of required strength (10 parts per 100,000). The inlet 
tubes were raised in the stoppers so that a short space was left between the 
surfaces of liquids and the ends of the tubes. The apparatus connected 
and complete with the contained solutions was then placed altogether in 
a steamer and sterilised for three successive days. 
A culture of the organism was divided into two equal parts, one half 
being heated to boiling for a minute or so, and further sterilised by placing 
in the steamer for three days at the same time as the apparatus described 
above. 
When sterile, the second flask was carefully disconnected from its stopper 
and sterilised or “dead” culture added, the flask being quickly reconnected. 
To the third flask the remaining half of the culture which contained the 
living organisms was added in exactly the same manner. The tubes, which 
had been raised to prevent “sucking back” of the solutions during cooling 
periods, were then pushed through the stoppers, care being taken that no 
portion of the tubes which had been previously exposed to the air occupied 
a position inside the flasks. 
The contents of flasks were then as follows :— 
Mask: ees es. xs Phenol solution alone. 
at wet Like asta cittatereect 5 a + dead culture. 
ap vi ae caret . - + living ,, 
RMT UALLN)  eietsceatias 3 3 alone. 
Air was slowly drawn through the solutions by means of an aspirator 
(rate 10 to 20 litres per day) in the direction of Flask I to IV. By this 
‘means the solution containing the living culture was kept free from air 
infection. Gelatine plates were made of all the solutions after the experi- 
ments, and the following is a general description of the bacteriological 
results obtained :— 
Flask I—(Phenol alone.) Very little contamination and occasionally 
none whatsoever. Not more than two organisms per cubic centimetre were 
present at any time. 
_ Flask II—(Dead culture.) Free from air infection. Plates of 1 ce. 
solution usually made. In one case great numbers of the chromogenic 
