PREFACE 



This book makes no pretense of being a treatise on the morphol- 

 ogy of bacteria, but is rather a record of personal researches under- 

 taken with the hope that by the "magic of numbers" some order 

 might be brought out of the chaos which has so far filled that field 

 of bacteriology w^hich has to deal with the form and structure of 

 bacterial cells. I must state frankly at once that I am no mathema- 

 tician. The expert in biometrics will therefore find here no such 

 carefully fitted curves and elaborate formulae as delight his heart, 

 but the ordinary person may follow my argument with only a very 

 elementary knowledge of statistics. With so poor a foundation I 

 should have been rather hesitant about publishing this work were I 

 not actuated by a conviction that the use of even such simple statis- 

 tical methods as I could handle has yielded truth of profound signfii- 

 cance not only for bacteriology, but for general biology as w^ell, and 

 by the hope that such publication may stimulate others more thor- 

 oughly equipped to enter this field of investigation. 



The history of the problem of morphologic variation in bacteria 

 is rather curious. The ideas prevalent in the early days of the science 

 — that bacteria possessed complex life cycles, that the various species 

 were freely transmutable, and that they were all perhaps but stages 

 in the development of some higher fungi — were completely upset by 

 the discovery of methods of pure culture, and replaced by the doc- 

 trine of monomorphism. This dogma has dominated the field ever 

 since, being opposed only in recent years by a minority of new 

 pleomorphists. So firmly has the monomorphistic viewpoint been 

 established that research on the problem has been almost completely 

 discouraged; bacteriologists have frequently noted that their organ- 

 isms appeared different from day to day, but have blindly con- 

 sidered all variations from the textbook picture as pathological, as 

 evidence of injury or death of the cells, or else have considered the 

 variations noted to be of such a haphazard character as to be of no 

 significance. The development of specific biochemical and sero- 

 logical reactions has made possible the identification of organisms 



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