VI PREFACE BY THE AUTHOR. 



or condition. Not infrequently 'the objects need to undergo, 

 in order to make them fit for use, some preliminary pre- 

 paration which may take several hours or even a day. The 

 student ought therefore to take cognisance of a lesson a 

 sufficiently long time before commencing work. 



The list of necessary reagents will be found at the end of 

 the book. These reagents should be ready before beginning 

 work. The method of preparation of special reagents for 

 histological work is also given in this list. Many of these 

 it is preferable to obtain ready-made from the firm mentioned 

 at the head of the list. 



The explanations and illustrations of the use of the in- 

 struments and reagents are scattered in the text ; but the 

 general index is made so far complete as to enable the 

 student easily to refer to any explanations which may be 

 necessary. 



I have given especial care to the methods of study of the 

 Bacteria; with the preparation which this book gives, the 

 student will be capable of following out any deeper researches 

 into this subject, as well as of realising their practical ap- 

 plication. 



All the figures in this work have been drawn by myself 

 from Nature. Almost all of the facts given in the text, even 

 those which were well known, have been submitted to careful 

 control. 



At the close of each chapter are given some bibliographical 

 notes, which show the student the fountain-head whence 

 fuller information can be obtained. 



ED. STEASBURGEE. 



