BACTERIOLOGY. 



HISTORICAL INTRODUCTION. 



Bacteriology as a science is a development of the latter 

 half of the nineteenth century. It may be said to have begun 

 with Koch's proof that Bacterium anthracis is the cause 

 of anthrax in 1876. Nevertheless this discovery of Koch's 

 was preceded by numerous observations and experiments 

 which led up to it. Some of this work was done in attempt- 

 ing to disprove the old "spontaneous generation" theory as 

 to the origin of organisms; some in searching for the causes 

 of disease and some in the study of fermentation and putre- 

 faction. 



SPONTANEOUS GENERATION. 



Speculation as to the first origin of life is as old as history 

 and doubtless older. Every people of antiquity had its own 

 legends, as for example, the account in Genesis. This ques- 

 tion never can be definitely settled, even though living 

 matter should be made in the laboratory. 



The doctrine of the "spontaneous origin" of particular 

 animals or plants from dead material under man's own 

 observation is a somewhat different proposition and may be 

 subjected to experimental test. ' The old Greek philosophers 

 believed it. Anaximander (b.c. 610-547) taught that some 

 animals are derived from moisture. Even Aristotle (B.C. 

 384-322) said that "animals sometimes arise in soil, in 

 plants, or in other animals," i. e., spontaneously. It can be 

 stated that this belief was general from his day down through 

 the Dark and Middle Ages and later. Cardano (a.d. 1501- 

 1576) wrote that water gives rise to fish and animals and is 

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