INTRODUCTION. IX 



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 insurmountable 

 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 recog- 

 nized as due the contributors whose unselfish aims have made it possible. 



CHARLES E. MARSHALL, EDITOR. 



EAST LANSING, MICHIGAN. 



