148 TOXINES AND ANTITOXINES. 



with diphtheria toxine and tetanus toxine, and hence PFEIFFER 1 

 asserted that cholera virus possessed a totally different nature 

 and mode of production to these true toxines. He put forward 

 the view that cholera virus was not an excretion product of the, 

 vibriones, but a substance firmly retained within the cell in the 

 normal condition, an " endotoxine," which only left the bacteria 

 after the death of the latter. This would account for the rela- 

 tively small toxic action of the filtered cultivations compared 

 with the highly poisonous effects of the living cultures, and, as 

 was shown by PFEIFFER, of the dead bacilli. 



PFEIFFKK advanced, in support of his view, the following facts 

 which he had observed : The germ-free filtrate of bouillon cul- 

 tures is only about half as poisonous as the original cultivation 

 before boiling. If boiled cultivations are filtered the germ-free 

 filtrate is more poisonous than that from the unboiled culture. 

 But if, on the other hand, the filtrate from the untouched culti- 

 vations is boiled, it loses its toxic property. 



If the vibriones are killed by means of chloroform or thymol 

 the poisonous property is retained, whereas the addition of 

 alcohol and precipitation with ammonium sulphate have an 

 injurious effect upon it. When the vibriones are allowed to 

 dry slowly, so that they die, they retain their toxic power. 

 If they are then heated with water and the liquid filtered 

 through a Chamberland filter, the filtrate is non-poisonous ; 

 nor is glycerin any more effective in extracting the poison 

 from the dead cells. PFEIFFER 2 concludes that there is a 

 primary very unstable poison which is converted by heat into 

 the secondary poison, prepared by SCROLL and others, which while 

 acting in the same manner is ten to twenty times weaker. 



PFEIFFER 3 still firmly maintained his theory even after 

 RANSOM 4 had claimed to have prepared, from cultivations, an 

 active cholera toxine possessing true immunising powers, and 

 after SoBERNHEiM 5 had, at an earlier period, obtained by filtra- 

 tion of old cultivations in a rapid state of decomposition a poison 

 that acted per os, and also produced immunity. RANSOM himself 



1 Pfeiffer, " Unters. lib. d. Choleragift," Zeit.f. Hyg., xi., 393, 1892. 



2 See also Pfeiffer, " Studien zur Cholera- Aetiologie," Zeit. f. Hyg., xv., 

 268, 1894. 



3 Pfeiffer, " Ueber die spezifische.n Antikorper der Cholera," Zeit. f. 

 Hyg., xx., 217, 1895; id., "Ein neues Grundgesetz der Immunitat," 

 Deutsch. med. Woch., 1896, Nos. 7 and 8. 



4 Ransom, "Choleragift u. Choleraantitoxin," Deutsch. med. Woch., 

 1895, 457. 



5 Sobernheim, " Experim. Unters. iib. Choleragift und Cholerschutz," 

 Zeit.f. Hyg., xiv., 485, 1893. 



