PATHOGENIC BACTERIA. 



PART I. GENERAL CONSIDERATIONS. 



INTRODUCTION. 



IT is incorrect to begin the consideration of bacteriol- 

 ogy, as is so often done, with the probable discoverer of 

 bacteria, Leeuwenhoek, or with the so-called "Father of 

 bacteriology, ' ' Henle. The controversies and ideas which 

 stimulated the investigations and researches which have 

 brought us to our present state of knowledge were begun 

 hundreds of years before the beginning of the Christian era. 



Excepting such as taught and believed that "in six 

 days the Lord made heaven and earth, the sea and all 

 that in them is," or a kindred theory of the origin of 

 things, the thinkers of antiquity never seem to have 

 doubted that under favorable conditions life, both animal 

 and vegetable, might arise spontaneously. 



Among the early Greeks we find that Anaximander 

 (43d Olympiad, 610 B. c.) of Miletus held the theory that 

 animals were formed from moisture. Empedocles of 

 Agrigentum (450 B. c.) attributed to spontaneous genera- 

 tion all the living beings which he found peopling the 

 earth. Aristotle (B. c. 384) is not so general in his view 

 of the subject, but asserts that "sometimes animals are 

 formed in putrefying soil, sometimes in plants, and some- 

 times in the fluids of other animals. ' ' He also formulated 

 a principle that "every dry substance which becomes 

 moist, and every moist body which becomes dried, pro- 

 duces living creatures, provided it is fit to nourish them." 



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