CONTRIBUTIONS TO 'THE CYTOLOGY OF THE BACTEKIA. 469 



during the process. There is therefore every reason to believe 

 that the centrally placed body is a living constituent of the 

 cell. It cannot be maintained that it is a non-living- structure 

 —for instance, a fat globule or metachromatic granule. 

 Now on purely morphological grounds, on analogy Avith what 

 is known of other cells, I think I am justified in calling this 

 centrally placed body in cocci a nucleus. It corresponds 

 as closely as could be desired with the structures which we 

 are accustomed to call nuclei in other cells. If it is not a 

 nucleus, then what is ity There is, I believe, only one 

 possible answer to such a question — that it may be a structure, 

 absent from other cells, which looks exactly like, and 

 behaves exactly like, a nucleus, but is really not a nucleus. 

 I think, therefore, that on morphological grounds it is com- 

 pletely justifiable to regai-d this body as a nucleus. More- 

 over, such a conclusion is considerably supported by the fact 

 that the structure is stained red by Romanowski's method — 

 the colour which is assumed by structures which are uni- 

 versall}^ admitted to be nuclei. 



The observations which I have made do not stand alone. 

 They are supported by the quite independent observations of 

 Nakanishi (1901) and Mencl (1910)i— both experienced 

 workers who employed reliable cytological technique. The 

 organisms studied by Nakanishi, Mencl and myself, though 

 all Coccus forms of Bacteria, are all different organisms, and 

 the cytological methods used were different in each case. 

 Both Nakanishi and Mencl, moi-eover, draw the same conclu- 

 sion as I do — tliouo-h not altogether from the same premisses. 

 They both believe that the structures which they discovered 

 are nuclei. 



The contention of Meyer (1908), that the nuclei described 

 by Nakanishi are really vacuoles, is hardly worth discussing; 



' I should like to point out — though of coiu'se I do not claim priority 

 in the discovery of mielei in Cocci— that luy observations were in no 

 way iuflnenced by the work of Nakanishi or Mencl. My own observa- 

 tions were made before I had seen Nakanishi's work, and two years 

 befoi-e the publication of Mend's paj)er. 



