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262 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 diarrhœa; 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 organisms 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 rapidly as it grew, and the bacilli die. When dried, they die within three hours; and they do not form spores. Micro-organisms possessing 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 appearance, 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 examination 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