THE 



UNIVERSITY 



OF 



CALIF 



BACTERIA IN RELATION TO 

 COUNTRY LIFE 



PART I 



STRUCTURE AND GROWTH OF BACTERIA 



CHAPTER I 



THE RISE OF BACTERIOLOGY 



BACTERIA are minute living things lying in the border- 

 land between plants and animals. Their existence was 

 undreamed of until times comparatively recent, yet 

 their appearance on the earth antedates that of man. 

 Plant and animal remains now turned to stone and 

 dating back to early geological ages have been found 

 to contain the petrified cells of bacteria, some forms 

 of which closely resemble those of today. 



We know that an almost endless number of plants 

 and animals now extinct have run their course on this 

 earth in passing from lower forms to higher, in adapting 

 themselves to a new environment. We do not know of 

 the cycles of change through which the bacteria have 

 passed, nor do we know of the birth and the passing of 

 forms long ago vanished. We know merely that in the 

 world of today their name is legion, that they differ not 

 only in form and size, but also in the chemical changes 

 that they produce. The rivers, the sea, and the earth all 



A (1) 



