12 L. A. JULIANELLE 



Effect of Heat on Hemolysis. Neisser and Wechsberg 2 found that 

 heating the staphylococcus "hemolysin" for 20 minutes at 56 C. would 

 completely inactivate it. 



In determining the effect of heat on the hemolytic action, the 

 supernatant fluids of centrifuged 9-day cultures were heated at 56 C. 

 for 30 minutes, and it was found that the hemolysin of staphylococcus 

 is a thermolabile substance, which can be destroyed by heating in 

 this way. 



DISCUSSION 



Previous investigators of the hemolytic activity of staphylococcus 

 were concerned with observations of the hemolytic activity per se. Aside 

 from some speculations as to its relation to pigment, virulence and 

 agglutination, no attempt was made to arrive at its causation. The 

 point under study here was concentrated on the cause of the hemolytic 

 activity, and the period of its development was only a coincidental 

 observation, since this phase of it was already sufficiently elaborated by 

 previous investigators. 



Our results point to a process of proteolysis perhaps associated 

 with autolysis -as the cause of hemolysis. This is not a new conception 

 it has been shown to be the fundamental of meningococcus hemolysis 

 and were experiments performed to establish the point of possibly B. 

 proteus, B. coli, etc. Although we have been unable to demonstrate 

 irrevocably that autolysis is the specific cause, it is very significant that 

 the period of maximum growth first appears, then the period of 

 maximum amino acidity, and, finally, the period of maximum hemolysis. 

 Such a sequence of evidence can point only to autolysis. 



It must be for this reason that we have been unable to suppress the 

 hemolytic activity of our hemolytic strains. If hemolysis is due to so 

 important a function as protein-splitting, the factor involved is too 

 vital to be eradicated by continued growth in blood-free mediums. 

 Conversely, it is no wonder that slowly hemolytic cultures will increase 

 in rapidity of hemolysis by continued adaptation to an environment 

 where protein ultilization becomes more pronounced. 



Nor is it phenomenal that sugar should not inhibit hemolysis in 

 such a case. Kendall and Walker's 15 conception that the presence of 

 glucose has a protein sparing effect and consequently retards production 

 of proteolytic enzymes can be accepted only provided the hydrogen-ion 

 concentration of the medium increases within suitable limits. For as 



15 Jour. Infect. Dis., 1915, 17, p. 442. 



