INTRODUCTION 



the material (namely, the animals killed in shorter or 

 longer times) is left unconsidered. As now the exactness 

 of the measurements increases sensibly with the material, 

 it is of importance to use the whole material. This may 

 be done in the following manner. The observations con- 

 tain many cases, in which doses larger or smaller than the 

 lethal dose have been injected. These observations offer 

 a statistical material of how many days " normal " guinea- 

 pigs live after injection of 1.5, 1.4, 1.3, 1.2, 1.1,0.9, -8> 0.7, 

 etc., lethal doses. By means of this statistical material the 

 reduction table given below was constructed, by the aid of 

 which all the data regarding the killed guinea-pigs may 

 be taken into consideration. 1 



In order to increase the statistical material, Madsen 

 proposed to consider the decrease of weight of the animals 

 in determining the lethal dose. 2 In this manner an in- 

 dependent determination was given for each series of 

 measurements. 



1 Arrhenius and Madsen : " Le poison diphterique," Oversigt danskc Vid- 

 sthkforh., Copenhagen, p. 269 (1904). 



2 Arrhenius and Madsen : I.e., p. 274. 



