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II. THE ENDOTOXINES. 



CHOLERA VIRUS. 



THE question of the nature of cholera virus, and of its position 

 with regard to the true toxines, is still far from being definitely 

 settled. Apart from the unfortunate fact that we meet with 

 direct contradictions in the experimental results, there is also 

 one very important circumstance that increases the difficulty 

 of making a survey in this and many very similar cases, such 

 as the poisons of typhus, pneumococcus, &c. The earlier 

 investigators of immunity were not at that time able to draw 

 the fundamental distinction between antitoxic and bacteri- 

 cidal immunity, and thus at first no systematic research was 

 made to determine the existence of a cholera toxine and anti- 

 toxine. But even at the present day the difficulty of investi- 

 gation is greatly increased by the fact that immunity against 

 cholera is undoubtedly, in the main, bactericidal, and that anti- 

 toxic immunity, even if it exists at all, occupies an absolutely 

 secondary position. Even inoculation with the dead cells 

 apparently produces a purely antibacterial immunity. 



The history of cholera virus begins with R. Kocn, 1 who had 

 long regarded cholera as a disease due to toxine poisoning, 

 although it was only after tedious experiments that he suc- 

 ceeded in causing rapid poisoning, and then only by means 

 of living bacteria. On the other hand, NICATI and RiETSCH 2 

 obtained poisonous filtrates devoid of specific activity, as was 

 also done by YAN ERMENGEM. S Then followed the usual inves- 

 tigations of the soluble crystalloid substances of a ptomaine 

 character which had been isolated from the cultures, but were 

 soon recognised as not responsible for the toxic action of the 

 vibriones. The toxalbumins, too, which BRIEGER and FRANKEL 

 isolated by their method from cholera cultivations, were found 



1 R. Koch, " Vort. uber die Cholera," Berl Idin. Woch., 1884, 498; id., 

 "Zweite Conferenz z. Erort. d. Cholerafrage," ibid., 1895 [37a], 8. 



2 Nicati and Rietsch, "Effets toxiques des produits, &c.," Comptes 

 Rend., xcix., 929, 1884. 



3 Van Ermengem, "Sur 1'inoculation des produits de culture du bacille 

 virgulse," Bull. Acad. Med. Be/g., [3], xviii., 1221, 1884. 



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