262 THE POPULAR SCIENCE MONTHLY. 



which the patients were suffering. They were present in the case 

 of all patients suffering from cholera, and in the bodies of all who 

 had died of it, whereas they were absent in the case of one patient 

 who had had time to recover from cholera, but had died of some 

 secondary complication ; and they were not discoverable in the 

 case of patients who, during the cholera epidemic, succumbed to 

 other diseases. They were also the same with the bacillus which 

 Dr. Koch had met the year before in the bodies of patients who 

 had died of cholera in India. From these causes the commission 

 felt justified in provisionally holding the belief that those bacilli 

 were in some way related to cholera, but were not yet prepared to 

 say whether they were the cause or the effect of the disease. In 

 1884 Dr. Koch visited Toulon, where cholera was raging, partly 

 at the wish of the French Government, which desired to know 

 more of his methods of investigating and suppressing the disease. 



The investigations of the German commission were continued 

 in India, and Dr. Koch's report on the subject was published 

 in the " Klinische Wochenschrift," of Berlin, No. xxxiv, 1884. 

 He had found, in the rice-water discharges of patients suffering 

 from cholera, besides the micrococci and bacilli common to the 

 evacuations of other patients, peculiar curved bacteria, which 

 have become known as " comma-shaped " bacilli, such as he had 

 not been able to discover in any cases of diarrhoea ; and he had 

 succeeded in isolating them by artificial culture. This he declared 

 to be a specific micro-organism having marked characteristics 

 distinguishing it from all other known organisms. These or- 

 ganisms grow rapidly in meat-infusion and blood-serum, and 

 well in other fluids, especially milk, and in potatoes ; and possess 

 the power of active motion. They grow best at a temperature of 

 between 30 and 40 C, and cease to grow at 16 C, but are not 

 killed by freezing. They grow only in the presence of oxygen, 

 and very fast ; their vegetation rapidly reaches its highest point, 

 then remains stationary for a time, after which it ceases as rap- 

 idly as it grew, and the bacilli die. When dried, they die within 

 three hours ; and they do not form spores. Micro-organisms pos- 

 sessing all of these and certain more delicate characteristics which 

 are definitely described, are Koch's bacilli ; organisms presenting 

 only some of the characteristics, such as microscopical appear- 

 ance, are something else. 



The presence of these bacilli in cholera, which was represented 

 as universal, was determined by microscopical examination in ten 

 cases in Egypt, and by microscopical examination and cultivation 

 in gelatinous meat-infusion in forty-two cases of post-mortem ex- 

 amination in India ; and in numerous other cases of dejections in 

 Egypt, India, and Toulon giving a hundred cases occurring in 

 various parts of the world, carefully examined, in which the 



