Agglutination of Encapsulated Bacteria. 53 



to occur also when four other strains of the same species, from 

 widely different sources, were tested. The bacteria agglutinated 

 in a dilution of the serum, ranging from 1-400 to 1-800. Two 

 strains of Bacterium ozcencB, one strain of Bacterium capsulatus 

 mucosus Fasching, and one strain of Bacterium pneumoniae. Fried- 

 lander, were not agglutinated at all by the same serum. The strains 

 of Bacterium rhinoscleromatis which agglutinated were no longer 

 encapsulated. All the other species still showed a capsule. One 

 of the strains of rhinoscleromatis when originally isolated was not 

 agglutinated by the serum of the patient from whom it was 

 isolated and at that time it was encapsulated (Thro, Proceedings 

 New York Pathological Society, April and May, 1910). This 

 microorganism, then, was not agglutinable when encapsulated 

 shortly after isolation. Later, it lost its capsule and became 

 agglutinable. As far as my work has gone, I have found that of 

 the species here considered rhinoscleromatis most easily loses its 

 capsule when grown on ordinary laboratory media and becomes 

 agglutinable. 



Beham has shown that encapsulated as well as non-encapsu- 

 lated species of this group have antigenic properties and may 

 produce agglutinins. I have no data on this point as yet. The 

 acid agglutination reaction of Michaelis, as modified by Beniasch 1 

 did not agglutinate Bacterium rhinoscleromatis without a capsule, 

 or Bacterium capsulatus mucosus possessing a capsule. 



Bacteria of the species here considered are not agglutinable 

 when encapsulated, but may become so when they lose their capsule 

 in the course of months of growth on laboratory media. Having 

 lost their capsules, these species may be differentiated by the 

 reaction of agglutination. Thus Bacterium rhinoscleromatis has 

 been shown to differ from Bacterium ozcenoe and from Bacterium 

 pneumonia. Friedlander, in that it more easily loses its capsule and 

 is then agglutinated by its specific serum. 



1 Beniasch, Zeitschrift fur Immunitatsforschung, Vol. XII, Heft 3, 1912, 268. 



