629 
very interesting subject, bringing to light a most interesting palae- 
ontological result and ably conducted, might have brought us still 
nearer to the trath if the Linnean method had been used in making 
the descriptions. 
This method indeed asks much of the investigator’s time and 
energy and the use of it can only be learnt by patient study. But 
we mean to say, that at some future time a botanist of Mrs. Srorns’ 
power will not be satisfied with descriptions of anatomical structures 
made without the use of the Linnean principles of micrography. 
Groningen, Oct. 21% 1912. 
Bacteriology. -— “On the reaction velocity of Micro-organisms’’. 
By Prof. C. ErsKman. 
(Communicated in the meeting of September 28, 1912). 
I. Velocity of disinfection. 
Micro-organisms have been the object of various researches as 
regards the velocity of their reaction, when exposed to external 
agents. From the experimental evidence brought forward it appeared, 
that considerable differences exist between individuals of the same 
species, of the same stock, nay of the same culture: they do not 
react all about at the same time, but the reaction proceeds in an 
orderly manner. 
It is especially the orderly progress of disinfection of bacteria, 
under the influence of germicidal agents, either chemical or thermal, 
which, in virtue of its vital importance for theory as well as for 
practice, has recently been studied by several investigators. 
Attempts have even been made to find a mathematical formula 
for this gradual process. As I stated before *) Mapsun and Nyman 
arrived at the conclusion’) that in the disinfection of anthrax spores 
the reaction proceeds according to the equation for the so-called 
“unimolecular reactions”. This view found favour with most experi- 
menters. 
When the reaction is illustrated graphically by plotting the results 
(abscissae representing the times and ordinates the numbers of survivors), 
a “curve of survivors” is obtained, having the shape of \. This 
1) Proceedings of the Meeting of 27 Feb. 1909, 
2) Z. f. Hyg. u. Inf. Kr. Bad. 57, 1907. 
