CHOLERA VIBRIO 505 



intoxication. These observers concluded from these experiments 

 that the cholera organism produced a soluble toxin which was dif- 

 fusible through collodion sacs. The toxicity of these cultures was not 

 destroyed by the boiling temperature, 100 C. They were able to 

 immunize guinea-pigs, rabbits, goats, and horses with this so-called 

 soluble toxin, and found the serum of these animals was antitoxic and 

 protective against several times the fatal dose of toxin or of the living 

 organisms. Antitoxic sera prepared by this method have not been 

 successful in the clinical treatment of cholera in man. It is not unlikely 

 that the soluble toxic substance or substances produced in artificial 

 cultivations of the cholera vibrio play a less important part in the 

 disease than the endotoxins, which appear to be liberated from the 

 organism with unusual readiness. 



The extremely brief period which elapses between infection and 

 death, twelve hours in unusual cases, would suggest that the incubation 

 period of the cholera toxin, if such play a part in the disease, is very 

 much less than that of any other known soluble bacterial toxin. 



Pathogenesis. Animal. Different strains of cholera vibrios vary 

 greatly in their virulence for experimental animals; prolonged cultiva- 

 tion on artificial media tends to diminish their pathogenicity as a 

 rule. Virulent cultures injected intraperitoneally in experimental 

 animals, particularly guinea-pigs, frequently cause acute peritonitis; 

 the animal gradually sinks into a state of coma, the temperature falls, 

 and death intervenes with or without convulsions. At autopsy the 

 peritoneum is reddened, the peritoneal surface of the intestines is 

 greatly congested, and there are usually small ecchymoses. There 

 is some increase in the peritoneal fluid, which frequently contains 

 vibrios. They may also be found in the blood stream as well. Sub- 

 cutaneous injections of like amounts of culture may or may not 

 result fatally. The organisms, however, as Theobald Smith pointed 

 out many years ago, tend to migrate to the intestinal tract, suggesting 

 that some chemotactic influence attracts them there. Intravenous 

 injection, particularly in young rabbits, may lead to lesions in the 

 intestinal tract, suggesting those characteristic of cholera in man, 

 but as a rule far less severe. The organisms may also be found in the 

 intestinal contents and gall-bladder following intravenous injection. 



Feeding experiments in the ordinary way are not successful. Koch 1 

 succeeded in infecting young guinea-pigs with cholera vibrios by first 



1 Deutsch. med. Wchnschr., 1885, No. 37a, 5-6. 



