24 ^^ CTEBIOL OGY. 



Simple and natural as all this may seem to us now, 

 the stage to which the subject had developed when these 

 observations were recorded did not admit of their meet- 

 ing with unconditional acceptance. The only strong 

 argument in favor of the etiological relation of the 

 organisms that had been seen, to the diseases with which 

 they were associated, was the constancy of this associa- 

 tion. No efforts had been made to isolate them, and 

 few or none to reproduce the pathological conditions by 

 inoculation. Moreover, not a small number of inves- 

 tigators were skeptical as to the importance of these 

 observations; many claimed that micro-organisms were 

 normally present in the blood and tissues of the body, 

 and some even believed that the organisms seen in the 

 diseased conditions were the result rather than the cause 

 of the maladies. It is hardly necessary to do more 

 than say that both of these views were purely specula- 

 tive, and have never had a single reliable experimental 

 argument in their favor. Billroth and Tiegel, who held 

 to the former opinion, did endeavor to prove their posi- 

 tion through experimental means; but the methods em- 

 ployed by them were of such an untrustworthy nature 

 that the fallacy of deductions drawn from them was 

 very quickly demonstrated by subsequent investigators. 

 Their method for demonstrating the presence of micro- 

 organisms in normal tissues was to remove bits of organs 

 from the healthy animal body with heated instruments 

 and drop them into hot melted paraffin, holding that all 

 living organisms on tlie surface of the tissues would be 

 destroyed by tlie higli temperature, and that if decom- 

 position should subsequently occur it would prove that 

 it was the result of the growth of bacteria in the depths 

 of the tissue to which the heat had not penetrated. 



