INTRODUCTION TO THE FIRST EDITION Xlll 



instruction as an essential factor to a working appreciation of the 

 subject. 



In matters of spelling, new words, and phrases, conservatism has 

 controlled. Arbitrary decisions and selections have been forced in 

 several instances to secure clearness, consistency and definiteness. 

 It is painfully evident to anyone attempting to bring system out of 

 the confusion and chaos existing in many fields of microbiological 

 action that some rearrangement ought to be undertaken. As usual, 

 however, this will be very slow on account of the many almost insur- 

 mountable difficulties. 



We need and invite helpful suggestions and criticisms at all times, 

 for a valuable text-book of the nature of this is one of slow growth and 

 development and not of "sport evolution." The editor is certain that 

 each contributor will welcome suggestions and, further, will be in far 

 better position to judge his own contribution after the material appears 

 in book form and has been submitted to students for which it is designed. 



No one better than the editor realizes fully the sympathetic part 

 played by the contributors. If any merit attaches to this book as it 

 finds its place in microbiological instruction, such merit should be 

 recognized as due the contributors whose unselfish aims have made it 

 possible. 



CHARLES E. MARSHALL, EDITOR. 

 AMHERST, MASSACHUSETTS. 



