Seeing that my results did not well agree with those of the above 
investigators, and this difference might possibly be based upon the 
fact that the dying off of the microbes was brought about by heat 
and not by chemical means, I have extended the investigation in 
this direction. Again bacillus coli communis was made use of, a 
bacterium forming no spores, while as disinfectant was used phenol 
in a concentration of at most 1 °/,, generally only */,°/,. The use 
of higher concentrations would make the process of dying off pass 
so quickly, that the time for a sufficient number of determinations 
would be too short, and among others the stage of incubation, if at 
all existing, would easily escape observation. 
In order to have no great differences between the individuals and 
accordingly to render the conditions as little complicated as possible, 
as a rule a fresh (broth) culture, only a few hours old, incubated at 
37°, was taken for the experiments, which culture, in its turn, had 
also been obtained by inoculation from a fresh culture. For the same 
reason the broth culture was slowly moved to and fro in a tube 
specialiy made for this purpose, which in an apparatus moved by a 
time-piece had been placed in the thermostate. Consequently all 
individuals were in well nigh equal conditions of development, so 
that the results of the experiments were more likely to be equivalent. 
Before we used the culture for the experiment, it was centrifugalized 
in order to remove the clots of bacteria, which were probably to be 
found in it and for obvious reasons would have a disturbing effect. 
Besides it was strongly diluted (+ 1000 times) with physiological 
common salt-solution. It would be necessary, in order to prevent 
sowing too many bacteria, to take of the non-diluted broth culture 
such small samples that, in measuring these, inevitably relatively too 
great mistakes would be made. 
The vessel with the diluting fluid, provided with the necessary 
quantity of the disinfectant, had already beforehand got the required 
temperature in a waterbath with a toluolregulator and an automatic 
stirring-apparatus. After the inoculation with the broth culture the 
mixture was constantly kept in motion by a glass stirrer, in order 
to make the disinfectant work as equally as possible upon all germs. 
As it is of great importance, to take the samples in rapid succession 
and just in time, I availed myself for this purpose of a peculiar 
kind of pipettes, which in case of immersion fill themselves automati- 
cally to the required height, so that the measuring, which takes 
up so much time, was avoided. The samples were put in Petri-scales 
and sown in melted, lightly alkaline reacting meat-agar. The develop- 
ment took place at 37°. The phenol put in the culture-plate together 
