252 Prof. M. C. Potter. Bacteria as [Jan. 18, 
conditions of treatment, and these were subjected to different temperatures of 
20°, 30°, 40°, and 100° C. The first three were maintained by Hearson’s 
incubators and the last by a steamer continuously boiling. Cloéz flasks were 
employed as before, each containing 5 grammes of the research material. 
The conditions selected for the purpose of experiment were :— 
(a) The Provision of Moisture surtable for the Growth of Micro-organisms.— 
The charcoal or coal in each flask, after inoculation, was moistened with 
distilled water, and the flasks then sealed. One of each kind was placed 
in the steamer, and the others in the incubators at the different temperatures. 
(b) Absolute Dryness which would inhibit Bacterval Life-—The flasks, after 
washing, were placed in a drying oven at 100° C., and then heated with the 
Bunsen flame while a stream of air dried by H2SO,4 was drawn through them, 
this operation being repeated several times. The coal and charcoal were algo 
dried for some hours at 100° C., and, while still hot, inserted in the flasks. To 
remove any trace of COs, air was again drawn through them, first passing 
through a Reiset with a strong solution of caustic soda and then through 
H.SO4 The flasks were sealed as speedily as possible and placed in the 
incubators. 
(c) Treatment uith Antiseptics—A. 2-per-cent. solution of corrosive sublimate 
and a solution of iodine in potassic iodide, 95 ¢.c. of water with 5 c.c. of solution of 
iodine (12°59 crammes I+ 18 grammes KI +1000 c.c. H20) were the antiseptics 
preferred, and an excess of chloroform vapour was also employed in deference 
to the prevalent idea that this substance can be relied upon as an antiseptic. 
The use of any carbon-compounds, however, such as chloroform or prussie 
acid, etc., was unsatisfactory, as a special investigation might be required to 
determine whether they were themselves responsible for any COz2 production. 
The whole series of flasks remained in the steamer and the various incu- 
bators for a definite period, after which a stream of air-free COz was drawn 
through the flasks, then through baryta solution, and titrations made. 
The results obtained with uncalcined charcoal are given in the table for the 
sake of comparison. 
The results as set forth in the above table show that under the conditions 
suitable for the growth of bacteria increasingly higher temperatures indicated 
a, corresponding increase in the amount of CQO» given off, the production at 
40° C. being greatly in excess of that at 20° C.; while at the temperature of 
100° C., at which active bacterial life would be impossible, there was no evolu- 
tion of COz. Also, under dry conditions which prevented bacterial growth, no 
CO, was evolved at any of the temperatures tried. 
The treatment with antiseptics proved to be untrustworthy and it was 
evident that this method must be abandoned and the results discarded as 
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