TEXT-BOOK OF BACTERIOLOGY. 25 



though it is not yet ten years since his methods of investigation 

 came into use. 



That in so short a time it has not been possible to accomplish 

 all that was required, is almost self-evident; but we may cherish 

 the certain hope that the near future will bring us further useful 

 discoveries, and that many further additions to our stock of knowl- 

 edge will yet be made by the application of new methods of inves- 

 tigation, next to be treated of. 



