128 THE ACUTE SELF-LIMITED INFECTIONS 



ized and the pig lives, although another animal receiving 

 the organisms in like quantity, but without serum, will 

 die. This is the method suggested which can be used 

 to identify suspected cultures, using as the protective 

 blood serum that from an animal previously treated 

 with known cholera germs. 



The cholera spirillum is a curved organism something 

 the shape of a comma, and is sometimes called the 

 comma bacillus. One end is apt to be thicker than 

 the other. It sometimes appears like an S when two 

 are joined on end. Long filaments may be seen in 

 fluids. In old laboratory cultures it may appear as a 

 short, straight rod or club. It is actively motile by 

 means of a long single flagellum on the end. No spores 

 are formed. It measures from inAnr to yjnnr mcn m 

 length by TSTIJT mcn m width. It is not easy to measure 

 since spirilla are not simple curves but spirals. It does 

 not stain with great ease, but a weak watery solution 

 of fuchsin is the best. It grows best in the presence of 

 oxygen at 37.5 C. or 98 F., but may grow at ordinary 

 temperatures. It has the power of digesting gelatin 

 and solidified blood serum, but does not clot milk. It 

 resists 60 C. or 142 F. for one hour, but boiling kills 

 at once. It multiplies at the temperature of foodstuffs, 

 and freezing does not destroy it under three days. 

 Drying kills certainly in twenty-four hours in diffuse 

 light. Sunlight kills within one hour. The figures 

 indicate some resistance to heat and light, but against 

 chemicals this is not maintained; 1 to 1000 bichloride 

 is fatal in ten minutes; 1 per cent, carbolic acid a 

 little longer; lime in any form is rapidly fatal to the 

 spirillum. 



