324 COLLECTED STUDIES IN IMMUNITY. 



a somewhat different receptor apparatus. It may be remarked that 

 the receptor apparatus of the bacteria need not permanently remain 

 the same qualitatively and quantitatively, as is well shown by some 

 experiments of mine in which I succeeded in producing a change in 

 these properties by means of cultivation. Thus after having grown 

 Kruse's bacilli on sterile milk 1 ten consecutive times (always trans- 

 planting on the second day), and finally transplanted it to agar, 

 it was found that this milk strain no longer showed the zone of the 

 proagglutinoid reaction. 



On making mutual absorption tests it was seen that the organism 

 was no longer like the original Kruse strain but entirety like that of 

 Flexner. That is to say, this cultivation on milk had effected a 

 gradual change in the Kruse strain which manifested itself in the 

 changed proagglutinoid zone of the absorption power. (See Table X.) 



It remains for further experiments in this direction to see whether 

 I shall succeed in cultivating the Milk-Kruse strain back to the original 

 Kruse strain, or in changing the Flexner strain into the Kruse strain. 

 Thus far the Flexner strain, as well as the Flexner strain altered 

 by cultivation, have preserved their properties for months. 



Resume. 



1. In the bactericidal tests, as well as in agglutination reactions, 

 my original dysentery strain from Japan proved entirely identical with 

 the two Kruse cultures. Since these are the most refined methods 

 at present at our disposal, there can be no doubt as to the identity 

 of my original cultures of 1897 with Kruse's bacillus of 1900. 



2. The dysentery immune serum derived from a horse and employed 

 by me for therapeutic purposes in 1898-1900 is of very high grade and 



1 This method of cultivation was really made because of the statement of 

 Celli ("Zur Aetiologie der Dysenteric, v. Leydens Festschrift") that my bacillus 

 would also coagulate milk like the bacillus found by him, if it was transplanted 

 8-10 times on alkaline milk. The result of my experiment was absolutely 

 different, for neither my original strain, nor the strain of Kruse, nor that of 

 Flexner coagulated milk when the cultures were grown on milk ten consecutive 

 times, provided care was taken to protect the milk from contamination. I had 

 already tested Celli's bacillus in Japan and found that it produced a considerable 

 amount of gas and coagulated milk, whereas my bacillus does not do this. In 

 view of this and of the further fact that Celli's bacillus does not agglutinate 

 with the immune serum produced by means of my bacillus, I conclude that these 

 two organisms are entirely distinct from one another a view which I have 

 already expressed in a previous communication. 



