186 CLINICAL BACTERIOLOGY. 



bacilli enter into contest with other microbes, the conditions 

 vary in accordance with the external temperature and the 

 amount of sodium chlorid present in the fluid in question. 

 The high temperature of summer and increase in the amount 

 of sodium chlorid favor the development of cholera-bacilli, 

 while at low atmospheric temperatures, or in the presence 

 of a small amount of sodium chlorid, they are quickly over- 

 grown by the associated microorganisms. If cholera- 

 dejections gain entrance into streams, the bacilli mostly 

 adhere to the particles of mucus, which they utilize as a 

 nutrient medium. They are thus often removed from the 

 influence of the current and the competition of other bac- 

 teria, and they not rarely maintain their vitality in streams 

 for a long time in spite of the unfavorable temperature and 

 the process of self-purification. 



The Occurrence of Cholera- vibrios. Comma-bacilli 

 are found constantly in all cases of Asiatic cholera, and 

 in innumerable amount ; in part, in pure culture in the 

 liquid intestinal contents ; further, in the intestinal walls of 

 patients 1 ; and only exceptionally in other organs. The 

 vibrios can be demonstrated in the feces on an average to 

 the tenth day after the inception of the disease ; not 

 rarely, however, for a longer time, and sometimes after the 

 termination of the disease (from the forty-sixth to the forty- 

 eighth day of convalescence). Comma-bacilli have never 

 been demonstrated in association with other diseases. Dur- 

 ing recent epidemics true cholera-bacilli were found repeat- 

 edly in the diarrheal stools of patients whose disease clini- 

 cally pursued a mild course and apparently bore no relation 

 to Asiatic cholera. It is possible, however, that these cases 

 represented the mildest grades of cholera, caused by bac- 

 teria of low degrees of virulence. Further, comma-bacilli 

 were found in some cases in the solid stools of healthy per- 

 sons subjected to bacteriologic examination only because 

 their relations brought them into the environment of 

 cholera-patients, or because they had drunk suspected 

 water, but who presented no symptoms of disease whatever. 

 It is probable that in these cases there existed a natural 

 immunity that permitted the passage of the vibrios through 

 the intestinal canal without injury. 



Outside the human body the cholera-bacillus of Koch 

 has been found in stagnant water in India, where cholera is 

 epidemic. In recent epidemics of cholera comma-bacilli 



