PREFACE 



For the past ten years it has been a part of the writer's duties 

 to give instruction in microscopical technique, and it has seemed 

 to him that there is need for a series of practical exercises which 

 will serve to guide the beginner through the maze of present-day 

 methods, with the greatest economy of time, by drilling him in a 

 few which are thoroughly fundamental and standard. The book 

 is intended primarily for the beginner and gives more attention 

 to the details of procedure than to discriminations between 

 reagents or the review of special processes. The student is told 

 what to do with his material, step by step, and why he does it; 

 at what stages he is likely to encounter difficulties and how to 

 avoid them; if his preparation is defective, what the probable 

 cause is and the remedy. In short, the book attempts to famil- 

 iarize the student with the little "tricks" of technique which 

 are commonly left out of books on methods but which mean 

 everything in securing good results. 



A very brief, non-technical account of the principles 

 of the microscope is inserted (Appendix A) with the 

 idea of giving the student just enough of the theoretical side of 

 microscopy to enable him to get satisfactory results from his 

 microscope. The microscope is so ably treated in the excellent 

 works of Gage (The Microscope] and Carpenter (The Microscope 

 and Its Revelations] that the writer feels himself absolved from 

 any further responsibility in this matter. 



The aim of the entire book is to be practical: to omit every- 

 thing that is not essential; and, above all, to give definite state- 

 ments about things. Appended to each chapter is a series of 

 memoranda which serve to supply additional information that is 

 more or less pertinent without obscuring the main features of the 

 method under consideration. 



In Appendix B the formulae for a number of the most widely 

 used reagents are given with comments upon their uses and manipu- 

 lation. Following this (Appendix C) is a concise table of a large 



