138 THE ACUTE SELF-LIMITED INFECTIONS 



almost pure culture, and can be made to grow quite 

 easily. There are several other spirilla of similar form 

 and manner of growth, and sometimes delicate bio- 

 logical tests (see below) are necessary. Agglutination 

 tests may be used in this disease, as some clumping 

 power is acquired by the blood during an attack. 

 Another antibody, a bacteriolysin, is formed, which 

 has the power of dissolving the cholera spirilla. 

 Animals injected with the cholera organisms also 

 acquire this power. If a guinea-pig be injected with 

 spirilla up to a point where it will resist large numbers, 

 its blood serum will dissolve the living organisms 

 either in the test-tube or, what is better, within the 

 abdominal cavity of another guinea-pig. In the latter 

 case the antiserum from the prepared guinea-pig 

 and living rods are mixed and injected together into 

 the peritoneal cavity. The rods are devitalized 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 -%-$$-$ to ^oVo mcn m 



