FURTHER STUDIES ON THE DYSENTERY BACILLUS. 313 



temperature, etc.)." In this connection I would call to mind the 

 bacillus of erysipelas of swine, whose immotility is still questioned 

 by many observers. I have always described the motility of my 

 cultures as feeble, though I found it strange that I was unable at 

 first to demonstrate flagella by staining methods. Later on, how- 

 ever, I succeeded in finding two terminal flagella in one preparation, 

 and thought that this question might now be regarded as closed. 

 To what extent this was an error I should not yet like to say, and 

 for the present I should also not like to regard the observations of 

 Vedder and Duval, 1 who found peritrichal flagella, as a confirma- 

 tion of my findings. 



In 1898 I immunized horses with dysentery bacilli and obtained 

 a high-grade serum with which in 1898-1900 almost three hundred 

 people have been treated. It therefore seemed advisable to study 

 this dysentery serum from the standpoint of the modern theory 

 of immunity. At the same time I was anxious by means of serum 

 diagnosis to again prove the identity of Kruse's bacillus with mine. 



The cultures employed were the following: One of my original 

 cultures, one from Prof. Flexner, one culture of the Kruse bacillus 

 from the Frankfurt Institute, and a Kruse bacillus from Dr. Conradi, 

 Berlin. I may at once say that in all the various bactericidal experi- 

 ments these cultures behaved exactly alike, and I shall therefore in 

 the following speak of the dysentery bacillus as such. When I come 

 to speak of the agglutination I shall make mention of certain variations 

 of Flexner 's bacillus from mine and Kruse's. 



To begin, the bactericidal action of normal active sera was tested 

 on the dysentery bacillus. The method employed corresponded 

 exactly to that described by M. Neisser and Wechsberg, to whose 

 paper I shall therefore refer. 2 



The amount of culture planted was always 1/500 mg. of a one- 

 day agar culture, and in the dilution employed this was contained 

 in 1.0 cc. salt solution. The total amount in each tube was always 

 2.0 cc., to which quantity three drops of bouillon were then added. 

 The serum was allowed to act for three hours at 37 C., after which 

 time six drops were made into agar plates. In judging the plates we 

 did not make use of accurate counting, but always employed the 



1 The Etiology of Acute Dysentery in the United States. Journal of Experi- 

 mental Medicine, 1902, Vol. VI., No. 2. 



2 See pages 120 et seq. 



