STAPHYLOCOCCUS PYOGENES AUREUS 393 



Toxic Products. Endotoxins. The dead bodies of staphylococci 

 injected into animals may occasionally give rise to abscess formation, 

 and, 21 if in sufficient quantity, may cause death. To obtain the latter 

 result, however, large quantities are necessary, the endotoxic sub- 

 stances within the dead cell body of these microorganisms being prob- 

 ably neither very poisonous nor abundant. 22 



That dead cultures of Staphylococcus aureus exert a strong posi- 

 tive chemotaxis for leucocytes was shown beyond question by the 

 experiments of Borissow. 23 



Hemolysins. In 1900 Kraus 24 noticed the hemolytic action of 

 staphylococci growing upon blood-agar plate cultures. Neisser and 

 Wechsberg 25 then showed that this hemolytic substance, secreted by 

 the Staphylococcus, could be demonstrated in filtrates of bouillon cul- 

 tures. Such hemolysins are produced by Staphylococcus aureus, and, 

 to a lesser degree, by Staphylococcus albus. The quantity produced 

 varies enormously with different strains and seems to be roughly 

 proportionate to the virulence of the particular microorganism, though 

 exceptions to this rule are not uncommon. Absolutely avirulent races 

 do not, so far as we know, produce hemolysins. Relationship of 

 hemolysin formation to virulence, however, is not by any means as 

 regular as at first supposed. A great many staphylococci may be 

 isolated from human lesions which produce absolutely no hemolysin. 

 The culture medium most favorable to the formation of these sub- 

 stances is, according to Neisser and Wechsberg, a moderately alkalin 

 beef bouillon. Cultivated at 37.5 C., the bouillon contains the maxi- 

 mum amount of hemolytic substance between the eighth and four- 

 teenth day, and this may be separated from the bacteria by filtration 

 through Berkefeld or Chamberland filters. We have not ourselves 

 attempted to confirm these investigations, but in the particular respect 

 of lateness of concentration in the cultures the Staphylococcus hemoly- 

 sin seems to differ distinctly from that produced by streptococci, in 

 which the optimum for a large yield is early, within the first twelve 

 or fourteen hours of cultivation. 



The hemolytic action may be observed by the general technique 

 for determining hemolysis (given on page 311). It is important to 



21 Scltattenfroh, Arch. f. Hyg., xxxi, 1887. 



22 v. Lingelslieim, "Aetiol. u. Therap. d. Staph. Krank.," Wien, 1900. 



23 Borissow, Zieglers Beitr., xvi, 1894. 



24 Kraus, Wien. klin. Woch., iii, 1900. 



25 Neisser und Wechsberg, Zeit. f . Hyg., xxxvi, 1901. 



