58 BACTERIAL POISONS OF INFECTIOUS DISEASES. 



precipitated. By collecting this precipitate and extracting it mth 

 sterilized water or physiological salt solution, the toxins only are dis- 

 solved. The belief that a separation of these two classes of proteids 

 can be made in this way rests upon the following assumptions, 

 neither of which can be said to be demonstrated facts : (1) The 

 poison and the immunizing body are not one and the same thing ; 

 (2) the cellular proteids are not soluble in water or salt solution. 



Hueppe claims, furthermore, that in a given case of cholera the 

 toxin may be formed most abundantly and the immunizing substance 

 only in small amount ; in such a case the symptoms of the disease 

 would be violent, and should recovery result, immunity to subse- 

 quent infection would be slight. With the conditions reversed, the 

 disease might be slight and the immunity established great. 



Pfeiffer and his students have held that the cholera toxin is an 

 integral part of the bacterial cell and that it is not set free or capable 

 of manifesting its toxic properties until the germ dies ; on the other 

 hand, Metschnikoff, Gruber, Behring, Ransom and others contend 

 that the living cholera germ produces both in vitro and in vita a 

 soluble, diffusible poison. It is not necessary to go into detail con- 

 cerning this discussion ; but we will give a brief statement of some 

 of the experiments made by Metschnikoff and Eoux. A collodion 

 sac of about 4 c.c. capacity, filled with a 2 per cent, pepton solution, 

 and inoculated with the cholera bacillus, was placed in the abdominal 

 cavity of a guinea-pig. A second animal received a similar sac con- 

 taining an emulsion of cholera bacilli killed by chloroform ; while a 

 third sac, containing pepton solution only, was placed in a third ani- 

 mal. Guinea-pig No. 3 remained unaffected ; No. 2 showed during 

 the first few days some slight elevation of temperature and some 

 emaciation ; while No. 1 died after from three to five days, with 

 symptoms of cholera intoxication. At autopsy the typical lesions of 

 cholera infection were found in the peritoneum, intestines, and kid- 

 neys ; while the cholera bacillus could not be found in the peritoneal 

 cavity, in the blood, nor in any of the organs. The collodion sac 

 contained a large culture of highly motile cholera bacilli but no leu- 

 cocytes. In order to obtain the toxin in artificial cultures, the germ 

 was made highly virulent by passage through animals and by sac 

 cultures. In this way they obtained a culture, -j^^ c.c. of which suf- 

 ficed to kill guinea-pigs. This highly virulent germ was grown in 

 a culture medium consisting of 2 per cent, pepton, 1 per cent, com- 

 mon salt, and 2 per cent, gelatin with some serum added. Cultures 

 in this medium, grown at 37° for from three to four days and filtered 

 through porcelain, killed guinea-pigs when administered subcuta- 

 neously in the proportion of one-third c.c. per 100-gram body weight. 

 The toxin thus obtained was not materially changed on being boiled, 

 but did lose its toxicity on contact with the air, especially when simul- 

 taneously exposed to light. Tubes completely filled with the germ- 



