428 m'laughlin and whitmore. 



spontaneous agglutination. These organisms had been kept upon labora- 

 tory media for many months. 



We found no instance of spontaneous agglutination, delayed agglu- 

 tination, or diminished agglutination when working with fresh cholera 

 strains, but in every instance they agglutinated promptly to the limit of 

 the specific serum and showed no tendency to spontaneous agglutination 

 in salt solution or serum other than specific cholera serum. 



Marked differences in the agglutinability of various cholera strains 

 of similar virulence usually does not exist. However, the four strains, 

 Abalogan, Berezosa, Leon and Solitana, required for agglutination much 

 stronger concentrations of cholera, sera than the other cholera strains. 



These were supposed to be strains of true cholera. They had been 

 isolated from typical cholera cases and agglutinated in the routine 

 manner by cholera serum in a dilution of 1-200. They were kept in 

 ordinary agar medium and transplanted about once eacli month during 

 July, August; September, and October. In November, cholera serum 

 Eegala. II agglutinated all of the other cholera strains in a dilution of 

 1-2,000 -f- and did not agglutinate the four above mentioned in any dilu- 

 tion weaker than 1-200. 



These cultures were carefully plated and the serum test repeated, 

 with the same result. Each of the four produces in a rabbit a serum 

 which agglutinates the homologous vibrio ; the other three strangely 

 acting vibrios, and all the cholera strains, in dilutions of from 1-1,000 

 to 1-2,000. 



Four new cholera sera were prepared from the freshly isolated cholera 

 strains, numbered 2, 4, 5 and 6, and the results may be seen in Table II. 

 With these fresh sera (numbered 2, 4, 5, and (i) it will be noted that 

 the strains Abalogan, Leon, and Solitana were not affected in the same 

 manner as other cholera strains, although the differences were not so 

 great as that shown by serum Eegala II. 



• The lowered agglutinability of these four strains was not in evidence 

 with all cholera sera. With the four homologous sera, and with one 

 of the El Tor sera (King B), these strains were agglutinated to the limit. 



It can not be said that the agglutinability always bears a fixed relation 

 to the virulence of an organism. Old, avirulent laboratory cultures, 

 Pfeiffer, Hankin, etc., are particularly susceptible to cholera sera ; agglu- 

 tinating in weaker dilutions than recently isolated strains. 



IIAEMOLYTIC PROPERTIES. 



The hamiolysing quality of certain vibrios has been the cause of 

 much discussion. 



Ruffer(lO) upon this group considers the El Tor vibrio to be distinct from 

 cholera, as none of his cholera strains possessed liEemolysing properties. Kolle and 



