8 4 



detect serious errors of observation, Koch's work stands 

 unchallenged more accurate and complete investigation 

 can scarcely be conceived. On the other hand, until 

 such repetition shall confirm Koch's observations, we 

 may justly decline to accept them unreservedly, on the 

 ground that he may have made his first error in this 

 his greatest effort. 



While, however, Koch's main assertion, that the bacilli 

 cause tuberculosis, can be competently criticised only 

 by the few men who like himself have the time, facilities, 

 and skill necessary to conduct such tedious and delicate 

 experimental observations, yet some of the preliminary 

 assertions fall within the range of a larger circle of critics, 

 and have been already subjected to extensive investiga- 

 tion. The results are as yet unanimous in confirming 

 the original assertions of Koch that the bacilli are to be 

 found in the sputum from most though not all cases of 

 pulmonary tuberculosis, and, what is quite as significant, 

 have never been found in any other sputum. 



Ehrlich, Balmer and Frantzel, Guttrnann, d'Espine, 

 Lichtheim, Frankel, Ziehl, Heron, Gibbes, Green, West, 

 Yeo, Whipham, Councilman, have already recorded their 

 unanimous experience that while the bacilli are found in 

 the sputum in at least a large majority of cases of pulmo- 

 nary consumption and tuberculosis, they are not found 

 in any other disease. Balmer and Frantzel found them 

 always in their one hundred and twenty cases, but never 

 in 'bronchitis. Ziehl recognized them in nearly all of 

 seventy-three cases, but never in thirty-four other cases, 

 including acute and chronic bronchitis, acute fibrous 

 pneumonia, gangrene of the lungs indeed all pulmonary 

 diseases that he had opportunity to examine. It should 

 be remembered that Koch failed to find them in the -spu- 

 tum from a certain number of cases. In the tubercles 

 of tuberculosis and in the cheesy matter of consumptive 

 lungs the bacilli are usually present not always, as 

 Koch himself discovered. Whether their absence from 

 certain tubercles is to be explained, as Koch suggests, 

 by the death of the organisms and their consequent fail- 



