EXPERIMENTS ON THE HUMAN SUBJECT 455 



and contain flakes of lymph, according to the stage at which 

 death takes place. If the dose is large, organisms are found 

 in considerable numbers in the blood and also in the small 

 intestine, but with smaller doses they are practically confined to 

 the peritoneum. Kolle found that when the minimum lethal 

 dose was used in guinea-pigs, the peritoneum might be free from 

 living organisms at the time of death, the fatal result having 

 taken place from an intoxication (cf. Diphtheria, p. 405). These 

 and other experiments show that though the organisms undergo 

 a certain amount of multiplication when introduced by the 

 channels mentioned, still the tendency to invade the tissues is 

 not a marked one. On the other hand, the symptoms of general 

 intoxication are always pronounced. 



Experiments on the Human Subject. Experiments have also 

 been performed -in the case of the human subject, both intention- 

 ally and accidentally In the course of Koch's earlier work, one 

 of the workers in his laboratory shortly after leaving was seized 

 with severe choleraic symptoms. The stools were found to 

 contain cholera spirilla in enormous numbers. Recovery, how- 

 ever, took place. In this case there was no other possible 

 source of infection than the cultures with which the man had 

 been working, as no cholera was present in Germany at the time. 

 AVithin recent years a considerable number of experiments have 

 been performed on the human subject, which certainly show that 

 in some cases more or less severe choleraic symptoms may follow 

 ingestion of pure cultures, whilst in others no effects 'may result. 

 The former was the case, for example, with Emmerich and 

 Pettenkofer, who made experiments on themselves, the former 

 especially becoming seriously ill. In the case of both, diarrhoea 

 was well marked, and numerous cholera spirilla were present in 

 the stools, though toxic symptoms were proportionately little 

 pronounced. Metchnikoff also, by experiments on himself and 

 others, obtained results which convinced him of the specific 

 relation of the cholera spirillum to the disease. Lastly, we may 

 mention the case of Dr. Orgel in Hamburg, who contracted the 

 disease in the course of experiments with the cholera and other 

 spirilla, and died in spite of treatment. It is believed that in 

 sucking up some peritoneal fluid containing cholera spirilla, a 

 little entered his mouth and thus infection was produced. This 

 took place in September 1894, at a time when there was no 

 cholera in Germany. On the other hand, in many cases the 

 experimental ingestion of cholera spirilla by the human subject 

 has given negative results. Still, as the result of observation of 

 what takes place in a cholera epidemic and of what has been 



