Bacteriology and Its Significance 35 



PRESIDENT'S ADDRESS. 



BACTERIOLOGY AND ITS PRACTICAL SIGNIFICANCE. 



Charles A. Behrens, Purdue University. 



Bacteriology has only recently been recognized as a cardinal science 

 — probably less than fifty years — although the diseases of smallpox, 

 rabies and plague were known hundreds of years before Christ and 

 occurred with the same lesions and characteristc symptoms as they do 

 today. 



The first glimpse into its mysteries was simultaneous with the in- 

 vention of the microscope. The origin of this instrument dates back 

 to the period of the "renaissance"; about the time Harvey discovered 

 the circulation of the blood. The real perfection of the microscope 

 was not accomplished until well into the nineteenth century. 



While bacteriology had its inception with the discovery of the 

 microscope and its development for a time kept pace with the per- 

 fection of this instrument, the study of bacteria as such, while very 

 important, was of interest only to the microscopist and botanist. 



It required such geniuses as Louis Pasteur and Robert Koch to 

 develop methods whereby one could correlate and associate the micro- 

 organisms revealed by the microscope to the phenomena they produced. 

 Thus the establishment of bacteriology as a modern practical science. 



If one were to review the early historical development of this 

 subject one would readily note that its forerunners were the ancient 

 ideas of superstition relating to disease; followed by the germ theory; 

 intermingled throughout with the theories of spontaneous generation 

 of life; the development of the compound microscope and the marked 

 stimulus it gave to investigational V\^ork in this field; the demonstration 

 of the facts revealing the definite role micro-organisms played in fermen- 

 tation and disease and finally the chemical and physiological develop- 

 ments. 



A comprehensive consideration of this extended field is generally 

 termed bacteriology and in practice it is the study of the smallest forms 

 of living matter, e. g., bacteria, yeasts, molds, transitional forms, pro- 

 tozoa and ultra-microscopic organisms (viruses) . 



However, the subject in its broader scope would be more correctly 

 called microbiology or better protistology. The word protist is about 

 the equivalent of the colloquial term germ and signifies the lowest form 

 of life whether plant or animal. The malaria germ, for instance, is an 

 animal while the pneumonia germ is a plant. 



All of these forms are important not only because they induce dis- 

 ease in man and animals but also because they are active in processes 

 of putrefaction and fermentation in dead matter. 



The nitrogen of the protein and the carbon of the carbohydrate 

 molecules are by these processes rendered available for plant life which 

 in turn are used by higher animals. 



"Proc. Ind. Acad. Sci., vol. 33, 1923 (1924)." 



