INTRODUCTION 



The advent of bacteriology into the realm of the 

 biological sciences not only brought with it a new con- 

 ception of the nature of many complicated phenomena, 

 such as fermentation and disease, but also placed in the 

 hands of experimental workers a new tool. The 

 method of sterilization, of asepsis, made it possible for 

 the first time to attack problems hitherto incapable of 

 solution, or even of approach. This development 

 of bacteriological technic, of rigid and undeviating 

 adherence to definite rules and principles, is not likely 

 to be passed over lightly by the historian of nineteenth- 

 century science. The art of practical medicine and 

 theoretical medical research alike owe much of their 

 recent brilliant success to a ready adoption of the new 

 method. 



At the present time an active campaign is being 

 set on foot by public health authorities against several 

 widespread and serious diseases of the human race. 

 In various parts of the world malaria, tuberculosis, and 

 typhoid fever are being fought energetically and with 

 much success. In these systematic and organized 

 movements the resources of bacteriology are being 

 utilized as never before, and a full understanding of 

 technical procedure and devices is deemed essential by 

 all workers in this subject. The problems of water- 

 supply and sewage disposal, of urban infantile mortal- 

 ity, and of the control of contagious diseases are all 

 bound up with the intelligent application of bacterio- 

 logical methods. 



