STREPTOTOX IN E. 165 



obtain by means of this preparation, insoluble in alcohol, the 

 typical general symptoms produced by the living cultivations. 

 His "poison" had, however, only a slight toxic activity (13 to 

 20 c.c. per kilo, of body weight) ; it was weakened, but not 

 destroyed, at 104 C. 



Most of these investigators, however, simply contented them- 

 selves with investigating the toxic action of filtered cultures, or 

 of cultures after sterilisation at 65 to 70 C., or by the addition 

 of O5 per cent, of phenol. 



SCHENK alone (loc. cit.) endeavoured to obtain a purer prepara- 

 tion by means of precipitation with zinc chloride and subsequent 

 treatment by Brieger's method. 



MARMOREK found that the toxine was weakened even at 58 C. 

 But the most important question, whether the poison thus 

 obtained does or does not produce antitoxic immunity against 

 the streptococcus, has not yet been definitely settled. 



ROGER (loc. cit.) found that his poison not only failed to pro- 

 duce any immunity, but that it even increased the susceptibility 

 to infection. 



SiEBER-ScHOUMOWA 1 was unable to effect immunisation by 

 means of filtered cultures. 



On the other hand, LAITINEN (loc. cit.) cultivated streptococci 

 on a 5 per cent, bouillon of peptone containing 2 per cent, of 

 glycerin and 0'3 per cent, of ordinary salt, and having an alka- 

 linity of 0'2 to 2 per cent., and precipitated from these cultures 

 by means of ammonium sulphate or amyl alcohol toxine prepara- 

 tions, which, when injected into the peritoneum in the proportion 

 of 0*1 to 0*4: c.c., or even of O'Ol c.c. on direct injection into the 

 nerves, killed large rabbits, while they also had the power of 

 conferring a certain degree of immunity against infection. 



PARASCANDALO (loc. cit.) laid special stress on the point that he 

 was best able to produce immunity against streptococci by means 

 of soluble toxines. 



He cultivated them on sugar bouillon, and, after sterilising them by 

 means of 0'5 per cent, of phenol, filtered the cultivations after twenty-four 

 hours through paper. He had found that simple filtration through porce- 

 lain did not remove all the living micro-organisms, which was also the case 

 on heating them to 60 or 70 C., although a higher temperature injured 

 the toxine. By making the first inoculations with the filtrates of young and 

 only slightly toxic cultures, he was able to immunise animals gradually 

 against large doses of very poisonous cultures, and in this way obtained a 

 true therapeutic serum. 



1 Sieber-Schoumowa, "Les serums therapeutiques anticocciques," Arch, 

 des Sciences Biol., iv., 415, 1896. 



