BACTERIA 



CHAPTER I 



THE BIOLOGY OF BACTERIA ' 



THE first scientist who demonstrated the existence of 

 micro-organisms was Antony von Leeuwenhoek. He 

 was born at Delft, in Holland, in 1632, and enthusiastically- 

 pursued microscopy with primitive instruments. He corro- 

 borated Harvey's discovery of the circulation of the blood in 

 the web of a frog's foot ; he defined the red blood corpuscles 

 of vertebrates, the fibres of the lens of the human eye, the 

 scales of the skin, and the structure of hair. He was neither 

 educated nor trained in science, but in the leisure time of his 

 occupation as a linen-draper he learned the art of grinding 

 lenses, in which he became so proficient that he was able to 

 construct a microscope of greater power than had been 

 previously manufactured. The compound microscope dates 

 from 1 590, and when Leeuwenhoek was about forty years old, 

 Holland had already given to the world both microscope 

 and telescope. Robert Hooke did for England what Hans 

 Janssen had done for Holland, and estabhshed the same 



' We propose throughout to use the term bacterium (pi. bacterid) in its generic 

 meaning, unless especially stated to the contrary. It will also be synonymous 

 with the terms microbe^ germ, and micro-organism. The term bacillus will, of 

 course, be restricted to a rod-shaped bacterium. 



