24 BACTERIOLOQY. 



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 speculative, and 

 have never had a single reliable experimental argu- 

 ment 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 

 employed by them were of such an untrustworthy 

 nature that the fallacy of deductions drawn from them 

 was very quickly demonstrated by subsequent investi- 

 gators. Their method for demonstrating the presence 

 of micro-organisms in normal tissue was to remove bits 

 of tissue from the healthy animal body with heated in- 

 struments and drop them into hot melted paraffin, hold- 

 ing that all living organisms on the surface of the tissues 

 would be destroyed by the high temperature, and that 

 if decomposition 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 pene- 

 trated. Decomposition did usually set in, and they 

 accepted this as proof of the accuracy of their view. 

 Attention was, however, shortly called to the fact that 

 in cooling the contraction of the paraffin caused small 

 rents and cracks into which dust, and bacteria lodged 

 upon it, could accumulate and finally gain access to 

 the tissues with the occurrence of decomposition as a 

 consequence. Their results were thus explained after a 

 manner analogous to that employed by Spallanzani, in 

 1769, in demonstrating to Treviranus the fallacy of the 



