HEMOLYTIC STAPHYLOCOCCI 23 



when the results were read. It was found that all strains reduced or 

 decolorized methylene blue at dilutions of 1 : 50,000 and 1 : 25,000; they 

 showed partial decolorization at dilution of 1 : 10,000, except strains T8, 

 C15 and Jl, which were negative; and at a dilution of 1 : 1,000 all the 

 strains were negative. 



Hydrolysis of Sodium Hippurate. Ayers and Rupp 48 found that 

 hemolytic bovine streptococci could be differentiated from the human by 

 the fact that the former could split sodium hippurate into glycocoll and 

 benzoic acid. We employed this test in our study to determine whether 

 such a procedure would be of value in differentiating the staphylococci. 

 The medium employed contained 1% peptone, 1% sodium hippurate 

 0.015% K 2 HPO 4 , and the reaction was adjusted to PH 7.2. The cul- 

 tures were incubated at 37 C. for 7 days. At that time hydrolysis was 

 determined by adding 0.5 c c of a 7 % FeQ 3 solution for every 2 c c of 

 the culture medium ; if hydrolysis had taken place an insoluble 

 precipitate was formed, whereas the mixture became clear on standing 

 several minutes if hydrolysis had not taken place. All the cultures were 

 able to split sodium hippurate. 



RELATION TO VIRULENCE 



Although Neisser and Wechsberg 2 showed that aureus and albus strains alike 

 are capable of hemolytic activity, their experiment seems to indicate that 

 purely saprophytic forms never attain this faculty. This was corroborated 

 later by Kutcher and Konrich 22 and also by Koch. 23 Noguchi in presenting 

 his results stated that hemolysis was proportional to the virulence of a strain, 

 but the evidence he presents does not justify such a conclusion. Montegazza * 3 

 was unable to demonstrate any definite relation between the intensity of an 

 infection and the quantity of hemolysin produced. 



In approaching an answer to the question of inter-relationship 

 between virulence and hemolysis, two methods present themselves 

 either hemolytic strains will prove to be virulent, or nonhemolytic strains 

 will be avirulent. 



Following the first method, then, strains A5, PI, P3 and T9, all 

 definitely hemolytic, were used. Twenty-four-hour broth cultures of 

 each were inoculated in 1 c c quantities into the peritoneum of separate 

 mice. No causalties occurring, the mice were killed, the peritoneums 

 were washed with sterile saline, and the washings injected into a fresh 

 mouse. Incidentally, cultures were made of the peritoneal exudate and 

 heart blood as a check. This procedure was carried successively for 



48 Personal communication. 



* Biochem. Centralbl. 1908, 8, p. 226. 



