CHAPTER II 

 HISTORICAL 



It must be evident that the science of hacteriology had its inception 

 with the discovery of the compound microscope. For some time the progress 

 in bacteriological investigation continued parallel with the progress in 

 the mechanical perfection of the microscope and with the advance in 

 microscopical technic. Gradually, however, the chemical and physio- 

 logical investigations pertaining to bacteria gained in importance and 

 significance. Our knowledge of the morphology of bacteria as revealed 

 through the compound microscope has been practically stationary for two 

 decades, but not so our knowledge of bacterial products and bacterial 

 action. The methods of bacteriological technology have been gra,dually 

 perfected, and the progress along this Una has kept pace with the chemical 

 and physiological investigations. 



Although, as indicated, the science of bacteriology is of comparatively 

 recent origin, yet we must not lose sight of the fact that many of the ideas 

 underlying this science, as now comprehended, were advanced in remote 

 antiquity. For this reason it is desirable to set forth these earlier concepts 

 in a historical review. Most of the writers on general bacteriology, who 

 make reference to the history of the subject, almost invariably mention 

 the older ideas regarding spontaneous generation as being the forerunners 

 of the modern ideas of bacteriology. It is, however, the ancient theories 

 and behef s pertaining to the cause of decay, disease, and epidemics which 

 are even more directly associated with the first more important discoveries 

 pertaining to modern bacteriological pathology. 



For the purposes of simplification, condensation, and greater clearness 

 the historical review is divided into periods or epochs. It is not possible, 

 in the following brief outUne, to cite all investigations of importance. 

 Only a few of the epoch-making specialists are mentioned. 



Period I 



From Hippocrates (300 B. C.) to Leeuwenhoek (1656). (The earliest 

 ideas regarding epidemics and spontaneous generation.) 



From the earhest times the more scholarly writers mentioned certain 

 noxious gaseous, and odoriferous substances or efiluvias as being the cause 

 of epidemics. These effluvias were supposed to emanate from the soil, 



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