PYOCYANEUS TOXINE. 129 



the main, remains attached to the cells themselves, it can be 

 separated almost completely from the cells in the case of pyocy- 

 aneus, so that we must assume that secretory processes occur 

 here similar to those that produce diphtheria toxine. 



B. pyocyaneus has a very characteristic behaviour, as was shown 

 by WASSERMANN. 1 Frequently it develops in the body of an 

 animal, and is thus infectious, and then the bactericidal protective 

 forces come pre-eminently into action. 



On the other hand, however, it develops in its cultivations 

 a true toxine, which can be separated from the cell substance, 

 and produces in the organism a true antitoxine. 



B. pyocyaneus thus occupies a very interesting intermediate 

 position between the purely toxic diphtheria bacillus, on the one 

 hand, and the bacteria of the cholera type, on the other hand, in 

 the case of which immunity is also pre-eminently bactericidal, 

 not antitoxic, while the supposed endotoxines have not as yet 

 been isolated in the free state. 



WASSERMANN proved that this poison could be* separated 

 almost completely from the bacilli, so that the cells, just as in 

 the case of diphtheria, contained practically no more toxine; 

 but, above all, he showed that by injection of the living bacilli in 

 small, but increasing, doses an immunising process results, which 

 was directed exclusively against the bacilli themselves, and had 

 absolutely no influence upon the poison. 



But, on the other hand, he succeeded in producing a true 

 antitoxic solution by means of the soluble poison. In this case 

 the serum had absolutely no bactericidal power in vitro ; yet, at 

 the same time, an animal rendered proof against the poison was 

 also immune against the living bacilli, just as in the case of 

 diphtheria ; for the bacilli, deprived of their keenest weapon, 

 their toxic function, are merely harmless intruders in the 

 organism rendered proof against the poison, and speedily perish 

 without inflicting any injury. 



WASSERMANN thus proved that B. pyocyaneus produced a true 

 toxine, which in this respect was undoubtedly akin to diphtheria 

 and tetanus toxine. It is somewhat more stable than these, 

 especially as regards its behaviour towards heat. It is not 

 completely destroyed even by boiling. 



In consequence of this a fact of theoretical importance was 

 established in the case of pyocyaneus poison. 



It was found that in a neutral mixture of pyocyaneus toxine 

 and antitoxine the latter could be completely eliminated by heat, 



1 Wassermann, "Unters. iib. einige theoret. Punkte d. Immunitatslehre," 

 Zeit.f. Hyg. y xxii., 263, 1896. 



