BACTERIOLOGICAL INTRODUCTION 11 



all the organisms represented in the following photo- 

 graphs are included amongst the Schizophytes. 



The cells in this group are chiefly remarkable in 

 that it has been impossible to demonstrate, with 

 certainty, a differentiation between the protoplasm 

 and the nucleus. 



The Schizophytes fall roughly into three morpho- 

 logical groups : — 



I. Cocci, comprising all those organisms whose 

 cells are spherical. 

 II. Bacilli, comprising the rod-shaped or cylin- 

 drical-celled organisms. 

 III. Spirilla, comprising the spiral or corkscrew 

 cells. 



This grouping cannot be regarded as strictly scientific, 

 but it is convenient. Owing to the undoubted poly- 

 morphism of these organisms a further convention is 

 required to make it a practical classification. The 

 bacilli are not unfrequently found in acoccoid form, 

 or in such extremely short cylinders that it is im- 

 possible to distinguish them from cocci. If, how- 

 ever, the apparent cocci are known to assume the 

 bacillary form under any conditions, then the organ- 

 ism is ranked under the group which may be 

 regarded as representing its highest form, assuming 



