A MANUAL OF BACTERIOLOGY 



INTRODUCTION 



BACTERIOLOGY is a branch of Biology which deals with 

 the study of Micro-organisms, particularly the minute 

 vegetable ones known as Bacteria. Its scope is ill- 

 defined, for the term is often used in a comprehensive 

 sense equivalent to micro-pathology, or even micro- 

 biology, and all investigations connected with micro- 

 organisms, animal and vegetable, may be included under 

 it. The subject has, however, become so extensive that 

 the unicellular animal forms are now being studied as 

 a separate branch, PROTOZOOLOGY. Bacteriology par- 

 ticularly deals with the functions of micro-organisms, and 

 their relation to processes disease, fermentation, putre- 

 faction, and the like while the study of their form, 

 structure, and life-history belongs to botany and zoology. 

 There is no space in this work to enter into the history 

 of the science, but the names of Leeuwenhoek (1675), 

 Miiller (1786), Schwann (1837), Cohn, Pasteur, Lister, 

 Koch and Ehrlich will ever hold an honourable place in 

 its annals. 



The study of micro-organisms is of importance in 

 general biology, for their vital phenomena are relatively 

 simple, and shed light on the more complex processes 

 occurring in the higher orders of living beings. Weis- 

 mann's theory of heredity is based upon what he terms 

 the " continuity of the germ plasm," which has as 

 a fundamental conception the immortality of these 



