14 



tubercle bacillus has been not only opportune 

 but convincing, and the work of de Schweinitz, 

 Trudeau, Pearson and Gilliland on immuniza- . 

 tion of animals against this organism bids fair 

 to make an advance step in the warfare against 

 this disease that will be of greater importance 

 than even the discovery of the causal organism 

 itself. 



It is also a matter of considerable pride that 

 American bacteriologists should have even been 

 the pioneers in some of the fields of research. 

 The demonstration of the etiology of plant dis- 

 eases of a bacterial nature is to be credited to 

 American bacteriology. The first studies on 

 this subject were made on the fire blight of 

 pears and apples by Professor Burrill, and to 

 him and a number of other workers belongs the 

 credit of proving the relation of this disease 

 to bacterial agency. The etiology of this dis- 

 ease has been as thoroughly proven as was that 

 of anthrax, all of the canons of Koch being ful- 

 filled, and yet this work is often not accepted 

 by many European workers. They consid- 

 ered the evidence as inadequate to show that a 

 causal relation existed between the organism 

 and the disease in question. 



It is surprising even yet to see the attitude 

 which is taken by many foreign writers on this 

 subject. Text-books of German origin often 

 wholly ignore the relation of bacteria to plants, 

 or pass it over with a brief reference in an 



