522 PATHOGENIC MICROORGANISMS 



solution, gave many of the usual proteici reactions, but differed from pro- 

 teids in failing to coagulate when boUed and in not giving precipitates 

 when treated with magnesium sulphate, sodium sulphate, or nitric acid. 

 It was believed by them to be closely related to the albumoses, bodies rep- 

 resenting intermediate phases in the peptonization of albumins. Similar 

 results have been obtained by Wassermann and Proskauer,' Brieger and 

 Boer,^ and others. Uschinsky,^ on the other hand, has disputed the 

 proteid nature of toxins in general and has succeeded in producing 

 diphtheria toxin by growing the organism upon a medium entirely free 

 from albuminous bodies. Uschinsky believes that the proteid reactions 

 observed by other workers may be due to ingredients of the precipitates 

 other than the toxin. It is not impossible, however, that the organ- 

 isms may have produced proteid substances by synthesis from the 

 simpler substances in Uschinsky's medium. The production of toxin 

 from such a medium, therefore, is not a conclusive argument against the 

 proteid nature of toxins. Accurate chemical isolation and analysis of 

 diphtheria toxin have not yet been accomplished. 



Diphtheria toxin is destroyed,^ when in the fluid form, by tem- 

 peratures of 58° to 60° C. In the dry state, it may resist a temperature 

 of 70° C. and over, without noticeable change. Light and the free access 

 of air produce rapid deterioration. Sealed, protected from light, and 

 kept at almost freezing point, the toxin remains stable for very long 

 periods. Electrical currents passed through toxic broth have little or 

 no effect upon it. 



Bacteria Similar to Bacillus Diphtherise. — Bacillus Hoffmanni 

 (Pseudodiphtheria hacUlus). — Hoffmann- Wellenhoff,^ in 1888, and, at 

 almost the same time, Loeffler,* described bacUIi which they had cul- 

 tivated from the throats of normal persons and in several instances from 

 those of diphtheritic persons, which were in many respects similar to true 

 B. diphtheriae, but differed from this chiefly in being non-pathogenic for 

 guinea-pigs. These organisms were at first regarded by some observers 

 as merely attenuated diphtheria bacilli More recent investigations, 

 however, prove them to be unquestionably a separate species, easily 

 differentiable by proper methods. They differ from B. diphtheria in so 



1 Wassermann und Proskatier, Deut. med. Woch., 1891, p. 585. 



2 Brieger und Boer, Deut. med. Woch., 1896, p. 783. 



3 Uschinsky, Cent. f. Bakt., xxi, 1897. 

 » Roux et Yersin, loc. cit. 



« Hoffmann-Wellenhoff, Wien. med. Woch., iii, 1888. 

 « Loeffler, Cent. f. Bakt., ii, 1887. 



