HEMOLYTIC STAPHYLOCOCCI 31 



These immunologic groups will perhaps explain the variations 

 experienced in curative and prophylactic inoculations of either the 

 organisms or serum. Stock vaccines, for example, will not necessarily 

 be specific, nor will immune serum prove to be efficacious unless it 

 falls into the same group. But having determined the group or type 

 of staphylococcus under question, we can employ specific material either 

 prophylactically or curatively. 



CONCLUSIONS 



Staphylococci produce a hemolytic substance in broth which appears 

 on the 6th day, reaches a maximum at the 9th or 10th day and then 

 disappears between the 13th and 16th day. 



This hemolytic substance is thermolabile, is unaffected by the 

 presence of carbohydrates and appears to be associated with proteolysis 

 and possibly autolysis. 



All cultures of Staphylococci isolated during the course of this 

 investigation appear to be hemolytic only the time of its manifestation 

 is in some cases considerably delayed. 



Hemolytic cultures did not lose their hemolytic powers by continued 

 transplantations into blood-free mediums for a period of more than 

 four months. 



Hemolytic activity shows no relationship to any of the biochemical 

 reactions studied. 



Staphylococci fix complement specifically, but cannot be classified 

 by such an expedient. 



Three groups seen definable of the 25 strains studied by agglutina- 

 tions and absorption test, with 2 ill-defined subgroups one each under 

 group 4 and group 3. 



These groups apparently bear no relationship to virulent hemolysis 

 or biochemical activity. Group 1 appears to include the light pig- 

 mented and less active strains. 



These groups may account for the variations experienced in the 

 past in the use of serum and vaccines. 



The writer wishes to express his sincere gratitude to Doctors A. C. Abbott and D. H. 

 Bergey for their invaluable assistance in advice, criticism and encouragement. 



