VI PREFACE TO FIRST EDITION 



the pieces of apparatus employed in a bacteriological 

 laboratory are novel even to the student trained in 

 chemistry and biology, and it has been thought best 

 to exhibit these, to the smallest detail, by means of 

 illustrations — a feature not sufficiently considered in 

 other guides. 



The formulae for stains and the methods of staining 

 have not been collected in one chapter, as is usually the 

 practice, because this tends to confuse the student. 

 They are described during the progress of the course, as 

 occasion offers to put them to practical use. 



Culture-description charts have not been included in 

 this volume. A beginner naturally makes incomplete 

 descriptions and many alterations, and thus defaces the 

 book and impairs its future utihty. A sufficient num- 

 ber of loose charts perforated for binding should be 

 furnished to the student at a nominal figure. 



A point of inestimable importance is how best to 

 stimulate the student to consult textbooks, special 

 monographs, and other references, as often and as 

 freely as possible. This guide has been written with 

 the aim of not only not interfering in any manner with 

 the reading, through including such points and char- 

 acteristics as might make a textbook superfluous in the 

 judgment of the inexperienced, but also of making it 

 necessary for the student to read the best textbooks 

 with freedom and understanding. Cultural and mor- 

 phological features are left entirely to the actual ob- 

 servation of the student, supplemented by instruction 

 and the reading of textbooks. 



The course, as outlined, is identical with the medical 

 course given at the University of Chicago, with a few 



