88 BACTEBIAL POISONS OF INFECTIOUS DISEASES. 



"Van de Velde ^ has ascertained that the staphylococcus pyogenes 

 produces a substance which destroys leucocytes and for wHch the 

 name " leukocidin " is now used. He injected sterilized cultures of 

 the staphylococcus into, the pleural cavities of rabbits and studied 

 the exudate which formed. He found that the leucocytes which are 

 present in such an exudate in large numbers soon undergo character- 

 istic changes. He next added to small quantities of the exudate 

 living, healthy leucocytes and observed that these underwent a like 

 transformation. Heating the exudate for ten minutes at 58° pre- 

 vents its action on leucocytes. The successive steps in the destruc- 

 tion of the white blood cells are as follows : (1) The leucocytes draw 

 in their pseudopodia and become round. (2) A light zone appears 

 in the periphery, while the center remains granular. (3) The light 

 zone gradually extends and the granulation completely disappears. 

 (4) The corpuscles are apparently reduced to empty sacs with scarcely 

 discernible nuclei which finally disappear altogether. These degen- 

 erative changes are complete in about two minutes. Similar changes 

 are observed in leucocytes added to either avirulent or virulent cul- 

 tures of the staphylococcus. These observations have been con- 

 firmed by BaiP and Lingelsheim.* Denys and Van de Velde* 

 have shown that the serum of animals rendered immune to the 

 staphylococcus pyogenes aureus destroys the leukocidin in cul- 

 tures of this germ. Neisser and Wechsberg ° have devised a 

 method of measuring the action of leukocidin and have decided 

 from their investigations that typical pyogenetic staphylococci, both 

 the aureus and the albus, produce the same leukocidin, but that 

 there are varieties of both these organisms which do not produce 

 this poison. 



Krauss* first observed that many red blood corpuscles are dis- 

 solved by filtered cultures of the staphylococcus. This hemolysin 

 has been fiirther studied by Neisser and Wechsberg, who designated 

 it as staphylolysin. This also is a product of both the aureus and 

 the albus. It is believed that this toxin possesses a constitution 

 similar to that supposed to be possessed by the diphtheria toxin ac- 

 cording to Ehrlich's theory, and that it consists of toxin and toxon. 

 Furthermore, it is probable that the toxin is converted into toxoids ; 

 but while the toxoids of the diphtheria toxin have the same avidity 

 for antitoxin as is possessed by the toxin, the toxoids of staphylotoxin 

 combine with antitoxin with less avidity than do the toxins. The 

 blood serum of healthy men contains an anti-staphylolysin, but that 

 from different individuals varies greatly. 



' La eeUide, 10. 



'Archivf. Hygiene, 32. 



" Aetiologie imd Tkerapie der Staphyhkokken-Ir^eetuynen, 1900. 



* La celltde, 11. 



5 Zenisehrifif. Iludene, 36. 



^ Wiener Hvn. Wodwnschrifi, 1900. 



