CHAPTER I 



Introduction 



MUCH of what has in the past been written of the morphology of 

 bacteria has been based upon the assumption that, because of 

 their small size, and the difficulty, by the methods usually employed, 

 of observing the complexities of their structure, they may be regarded as 

 simple in form and primitive hi philogeny. 



The temptation to regard small size, and simplicity of structure, whether 

 real or apparent, as criteria of a primitive condition, has often proved the 

 cause of error and confusion in the classification of other groups of living 

 organisms. As more information becomes available it is almost invariably 

 discovered that the simplest creatures exhibit characters which suggest a 

 relationship with others, much more complex, or may themselves prove to 

 be less simple than they had been believed. This has proved to be true of 

 bacteria also. Although for long believed, in spite of much evidence to the 

 contrary, to be almost structureless cells, reproducing by simple fission, they 

 have proved to possess an intricacy of structure rivalhng that of any other 

 type of living cell, and to undergo life-cycles of considerable complexity. 



There is little doubt that the reason why so much more has been learned 

 of the physiology of bacteria than of their morphology, is their very great 

 importance in medicine, industry and agriculture. The immediate, practical 

 problems ot bacteriology have overshadowed the more academic questions 

 of their biological nature. The techniques which were devised for the solution 

 of these problems have been notable, in almost every case, for their failure 

 to provide even a minimum ot basic, biological information. Indeed it may 

 be said that much of the information o( this nature, accumulated since the 

 commencement of systematic bacteriology, has tended rather to obscure 

 than to clarify the underlying truths. 

 ( Especially is this true of the staining techniques employed tor routine 



