A STUDY OF SPONTANEOUS AGGLUTINATION 81 



can be determined by plating the culture and observing the two 

 types of colonies. If flocculi, pellicles or small clumps are pres- 

 ent in a twenty-four hour sub-culture of a non-spontaneously- 

 agglutinating strain, we can assume that it has changed its 

 characteristics and expect to find both types of growth present. 



VAHIATION IN GROWING POWER OF THE SPONTANEOUS AND NON- 

 SPONTANEOUS AGGLUTINATION COLONIES FROM ONE STRAIN 



Dreyer, using stock cultures for the agglutination test, passed 

 a strain through several sub-cultures on broth medium and then 

 treated a vigorously growing sub-culture with formalin. He 

 reports that agglutination reactions with such cultures are more 

 powerful. 



Block (1897) claims that if too frequent transplantation of 

 the culture is made there will occur in time spontaneous agglu- 

 tination. This is possible only if an easily changeable strain 

 containing spontaneous and non-spontaneous agglutination types 

 is used. After isolating the non-agglutinating type of colony 

 two broth cultures were made from a single colony, one of which 

 was daily transplanted into fresh broth. After several days in 

 the agar plate from the sub-cultures many colonies of sponta- 

 neously agglutinating types were present, while in the first broth 

 culture which was not transplanted, there were only a few col- 

 onies of the spontaneously agglutinating types. Our deduction 

 from these experiments is, that the type of organism showing 

 spontaneous agglutination grows more vigorously than the non- 

 spontaneously-agglutinating type taken from the strain in these 

 experiments. On the other hand, if the growth of the non-spon- 

 taneously-agglutinating strain is stimulated, one will find that 

 the spontaneously agglutinating type is weakened greatly and, in 

 some cases, entirely disappears. 



Experiments were made on growing the two types of culture 

 together in broth, as follows: Broth cultures were prepared con- 

 taining one loopful of a spontaneous and one, of a non-spon- 

 taneous agglutination type of organism. The results as showTi 

 on agar plates made at the end of each twenty-four hours varied 

 widely. In some the growth of non-spontaneously agglutinating 



