PREFACE TO THE THIRD EDITION. 



A LITTLE over a year has passed since this book 

 appeared, and a third edition has become necessary. In 

 this I have made a number of alterations and additions. 

 Some of the methods of preparing nutritive-media have 

 been simplified, while others have been described more 

 in detail. The methods of staining have been revised, 

 and a number of facts bearing on septic and specific 

 organisms, gained during the past year or two, have been 

 added. I trust that this revision will add to the value 

 of the work. 



E. KLEIN. 



November, 1885. 



