574 Asiatic Cholera 



The luxuriant development of the spirilla in the liquefying gelatin 

 is followed by the formation of considerable sediment in the lower 

 third or half of the liquefied area. This solid material consists of 

 masses of spirilla which have probably completed their life-cycle and 

 become inactive. Under the microscope they exhibit the most 

 varied involution-forms. The liquefaction reaches the sides of the 

 tube in from five to seven days, but is not complete for several 

 weeks. 



Agar-agar. — When planted upon the surface of agar-agar the 

 spirilla produce a grayish-white, shining, translucent growth along 

 the entire line of inoculation. It is in no way peculiar or char- 

 acteristic. The vitality of the organism is retained much better 

 upon agar-agar than upon gelatin, and, according to Frankel, the 

 organism can be transplanted and grown when nine months old. 



Blood-seriun. — The growth upon blood-serum is also without 

 distinct peculiarities; gradual liquefaction of the medium occurs. 



Potato. — Upon potato the spirilla grow well, even when the 

 reaction is acid. In the incubator, at a temperature of 37°C., a 

 transparent, slightly brownish or yellowish-brown growth, some- 

 what resembling that of glanders, is produced. It contains large 

 numbers of long spirals. 



Bouillon. — In bouillon and in peptone solution the cholera organ- 

 isms grow well, especially upon the surface, where a folded, wrinkled 

 pellicle is formed, the culture fluid remaining clear. 



Milk. — In milk the growth is luxuriant, but does not visibly 

 alter its appearance. The existence of cholera organisms in milk 

 is, however, rather short-lived, for the occurrence of acidity destroys 

 them. 



Vital Resistance. — Although an organism that multiplies with 

 great rapidity under proper conditions, the cholera spirillum does 

 not possess much resisting power. Sternberg found that it was 

 killed by exposure of 52°C. for four minutes, but Kitasato found that 

 ten or fifteen minutes' exposure to 5S°C. was not always fatal to 

 it. In a moist condition the organism may retain its vitality for 

 months, but it is very quickly destroyed by desiccation, as was 

 found by Koch, who observed that when dried in a thin film its 

 power to grow disappeared in a few hours. Kitasato found that 

 upon silk threads the vitality might be retained longer. Abel and 

 Claussen* have shown that it does not live longer than twenty or 

 thirty days in fecal matter, and often disappears in from one to 

 three days. The organism is very susceptible to the influence of 

 carbolic acid, bichlorid of mercury, and other germicides, and is 

 also destroyed by acids. Hashimotof found that it could not live 

 longer than fifteen minutes in vinegar containing 2.2-3.2 per cent, 

 of acetic acid. 



* "Centralbl. f. Bakt. u. Parasitenk.," Jan. 31, 1895, vol. xvii, No. 4. ' 

 t "Kwai Med. Jour.," Tokyo, 1893. 



