HAROLD C. ERNST l6/ 



I lay much stress upon my own line of work, because of 

 course I am more familiar with that than with any other ; 

 but, as I have stated, this line of work is dependent upon 

 animal experimentation from beginning to end, not only in 

 itself, but as drawing upon the results of the same line of 

 work in other lines of investigation. 



The changes in medical knowledge have been many and 

 of vast importance, and it would seem, if our just hopes are 

 gratified, that more important changes are still to come. 



Necessarily, since the discovery of ether, no event has so 

 profoundly influenced medical practice and teaching as the 

 realization by the medical profession of the tremendous 

 importance of the theory of bacterial infection. Ether it- 

 self would not have proved the blessing it has, if the 

 knowledge of surgical fever, of septicemia, pyemia, and 

 similar processes had not been made as clear as has been 

 the case. Of course the knowledge of bacterial infection 

 does not in any sense cover the whole field of medical 

 advance, but it is of itself one of the great steps of the 

 century in medicine, and much of our exact knowledge of 

 etiology is dependent upon it. 



It is the general knowledge of etiology and public hy- 

 giene that has most benefited by the increase in our knowl- 

 edge of the bacteria, and this increase in knowledge has 

 been dependent upon the destruction of the old theory 

 of spontaneous generation. Until this could be definitely 

 done away with, it was not possible to secure much support 

 for a belief in the assertions as regarded the specific nature 

 of the bacteria. 



Through this theory of the action of the bacteria in the 

 production of disease, we have gained a practical working 

 knowledge that is of incalculable value in the management 

 of these processes, even though our hopes of securing a 

 specific means of treatment have not yet reached their full 

 fruition. What better illustration of this can be given than 



