30 THE BACTERIA IN ASIATIC CHOLERA. [CH. 



( wenige or sparliche ), in one none could be found; then 

 out of twenty-four cases dead between twenty-four and forty- 

 eight hours there was one without the comma-bacilli, one 

 was questionable, and in nine cases the comma-bacilli were 

 scarce ( sparlich or wreinzelt ). These facts then of Drs. 

 Weisser and Frank do not seem to agree with the con- 

 clusions they draw (I.e. p. 390), but they singularly harmonise 

 with my own statements, viz., that there does not exist any 

 definite and uniform relations between the severity and 

 rapidity of the disease and the number of comma-bacilli 

 present in the intestine, as was maintained by Koch. 



(c] The statement of Koch that the comma-bacilli in the 

 acute stages are present in the tissue of the mucous 

 membrane of the ileum requires the most serious considera- 

 tion. If it were true that in the acute stages of the disease, 

 the comma-bacilli are constantly present in the tissue of the 

 mucous membrane in the definite manner described and 

 figured by Koch, i.e. in the epithelium and superficial mucosa, 

 around the Lieberkiihn's follicles, and in the peripheral 

 zones of the lymph-follicles of the Peyer's glands, then a 

 very important point in the chain of evidence would thereby 

 be established. One of the most essential and generally 

 acknowledged requirements in proving the connection 

 between a definite species of bacterium and the causation 

 of an infectious disease is the constant presence of this 

 particular species in the diseased tissues. Although complete 

 proof is not thereby given, yet it must be obvious that the 

 constant presence in large numbers of a definite species in 

 the diseased tissues cannot be of an indifferent nature. In 

 all those cases of infectious disease in which a definite 

 species of bacterium has been unequivocally proved to be 

 the cause of the disease, this constant presence of that 

 definite species of bacterium has been established. 



