6io 



Asiatic Cholera 



water from polluted gutters; how they enter milk with water used 

 to dilute it; how they appear to be carried about in clothing and 

 upon food-stuffs; how they can be brought to articles of food by flies 

 that have preyed upon cholera excrement; and other interesting 

 modes of infection. The hterature is so vast that it is scarcely 

 possible to mention even the most instructive examples, A bacteri- 

 ologist became infected while experimenting with the cholera spirilla 

 in Koch's laboratory.* It is commonly supposed that the cholera 

 organism may remain alive in water for an almost unUmited length 

 of time, but experiments have not shown this to be the case. Thus, 

 Wdghiigel and Riedel have shown that if the spirilla be planted 

 in sterihzed water they grow with great rapidity after a short time, 



Fig. 243. — Spirilla of Asiatic cholera, from a bouillon culture three weeks old, 

 showing long spirals. Xiooo (Frankel and PfeifEer). 



and can be found ahve after months have passed. Frankel, how- 

 ever, points out that this ability to grow and remain vital for long 

 periods in sterihzed water does not guarantee the same power of 

 growth in unsterilized water, for in the latter the simultaneous 

 growth of other bacteria serves to extinguish the cholera spirilla 

 in a few days. 



Morphology.— The micro-organism is a short rod i to 2 /< in 

 length and 0.5 /z in breadth, with rounded ends, and a distinct curve, 

 so that the original name by which it was known, the "comma 

 bacillus," applies very well. One of the most common forms is that 

 in which two short curved individuals are conjoined in an S-shape. 



When the conditions of nutrition are good, multipUcation by fission 

 progresses with rapidity; but when adverse conditions arise, long 

 spiral threads — -unmistakable spirilla — -develop. Frankel found 



*Deutsche. med. Wochenschrift, 1885, No. 37, a, 7. 



