XATURE OF SUBSTANCES CONCERNED IX AGGLUTINATIOX 183 



FIG. 72 



Showing the effect of saturating with bacilli of types Shiga-Manila and Mt. Desert, a serum from 

 a horse which had received combined injections of dysentery bacilli of the three types. Note that 

 the Manila type removed almost all the specific and group agglutinins acting upon its own type and 

 the group agglutinins acting upon the Coney Island and normal types, leaving the specific aggluti- 

 nins for types Shiga and Mt. Desert. The same is true for types Shiga and Mt. Desert when they were 

 used. 



Manila paradysentery. Mt. Deert paradysentery. 



Japan paradysentery. and Atypical paradysentery. 



The absorption method simply proves, therefore, that when one 

 variety of bacteria removes all agglutinins for a second the agglutinins 

 under question were not produced by that second variety. 



Loss of Capacity in Bacteria to be Agglutinated or to Absorb Agglu- 

 tinins Because of Growth in Immune Sera. The loss of these charac- 

 teristics by growth in sera has been demonstrated by Marshall and 

 Knox. The experiments of Dr. Collins and myself are recorded be- 

 cause they were undertaken in a slightly different way and also because 

 a certain number of confirmatory observations are of value. 



The maltose fermenting paradysentery bacillus of Flexner was 

 grown on each of eleven consecutive days in fresh bouillon solutions 

 of the serum from a horse immunized through oft-repeated injections 

 of the bacillus. The solutions used were 1.5, 4, and 15 per cent. The 

 serum agglutinated the culture before its treatment in dilutions up to 

 1 : 800, and was strongly bactericidal in animals. After the eleven 

 transfers the culture grown in the 15 per cent, solution ceased to be 

 agglutinated by the serum and ceased to absorb its specific agglutinins. 

 The cultures grown in the 1.5 and 4 per cent, solutions agglutinated 

 well in dilutions up to 1 : 60 and 1 : 100 and continued to absorb agglu- 

 tinins. The recovery of the capacity to be agglutinated was very slow 

 when the culture was from time to time transplanted on nutrient agar. 

 After growth for sixteen weeks, during which it was transplanted forty- 

 three times, it agglutinated in dilutions of 1 : 200. The culture grown 

 in 4 per cent, agglutinated 1:500, and the one in 1.5 per cent. 1:800. 

 This diminution and final cessation of development of agglutinable 

 substance in bacteria grown in a serum rich in agglutinin and immune 



