420 MICRO-ORGANISMS AND DISEASE [chap. 



faintly stained spirilla," and until this is done I maintain that 

 they are detached flagella (probably of bacillus coli) which 

 have become stained, and that there exists something in the 

 watery stools which acted hke a mordant and which makes 

 the flagella susceptible of becoming stained. 



The comma bacilli occur in cholera as a rule only in the 

 cavity of the small and large intestines, chiefly the lower 

 part of the ileum and large intestine ; no bacteria occur in 

 the blood or other tissues. Comma bacilli and also other 

 bacteria may and sometimes do immigrate into the tissue of 

 the wall of the ileum, and in a few cases have been traced 

 even as far as the liver and gall-bladder ; but in the large 

 majority of cases the comma bacilli are limited to the con- 

 tents of the ileum and large intestine and the superficial 

 parts of the internal surface of the mucous membrane of the 

 ileum. For this reason Koch maintained that the disease 

 is an intoxication, that is, it is caused by a chemical poison 

 which, being elaborated by the comma bacilli within the 

 intestine, is absorbed into the blood, and hereby sets up the 

 disease cholera. 



The comma bacilli of Asiatic cholera show on cultivation 

 in nutrient gelatine well-defined appearances, which enable 

 us to recognise them, so much so that in suspicious cases 

 of cholera their demonstration by cultivation in the evacua- 

 tions is of diagnostic value. But in connection with this it 

 must be borne in mind that in some cases or in non-typical 

 cases their demonstration by the gelatine culture test, owing 

 to the vast predominance of other bacteria, is a matter of 

 some difficulty. Where they are present in large numbers 

 their demonstration by the gelatine culture test is a matter 

 of comparative ease. All that is necessary is to place a 

 small flake of the evacuation into a few (8-10) cubic centi- 

 metres of sterile (well-boiled) salt solution, shake it well up. 



