14 ESSAYS ON BACTERIOLOGY. 



Tlie rise of the germ theory of disease, as we now 

 know it, is one of those great movements — ^wide, deep 

 and far-reaching, such as are seen only now and then 

 in the progress of medicine, and which stamp the 

 character of its succeeding generations. It has modi- 

 fied and advanced otir ideas of etiology; it has entered 

 the field of pathology and wrought great changes in 

 it, so that, for instance, we now saj, in the language 

 of Strumpel: "The definition of tuberculosis has 

 now removed itself from a merely anatomical basis; it 

 is that disease which is called forth by the active 

 agency of the tubercle bacillus." Dr. Senn has re- 

 cently expressed the opinion, the truth of which I 

 neither deny nor afiirm, that "more real progress has 

 been made in surgical pathology during the last fif- 

 teen years than in twenty centuries preceding," and 

 that "surgical pathology has become almost synony- 

 mous with surgical bacteriology." Though to a lim- 

 ited extent, yet distinctly and helpfully, it has in- 

 creased our diagnostic abilities; it has added some- 

 thing to medical treatment, and has aroused, stimu- 

 lated, and guided many earnest efforts in this direc- 

 tion. It has strengthened the safeguards about the 

 puerperal woman, and so modified the methods of sur- 

 gery and emboldened its practice as to add much to 

 its efiiciency. It has entered the broad realm of sani- 

 tary science and preventive medicine, and, throwing a 

 new ray of light toward that promised land, has 

 brightened our hopes for the coming of a better day. 



