CONTRIBUTIONS TO THE CYTOLOGY OF THE BACTERIA. 473 



The aggregate of these masses in each cell is the morpho- 

 logical equivalent of the chromidia or the spiral filament. 



Thus, we see here another modification of the nucleus 

 which may exist in Bacteria. 



I will now consider the spirillar forms which I have in- 

 vestigated. I have found that three different types of 

 structure exist in these organisms. In one of these tliere is 

 a minute spherical body present in each cell : it divides with 

 a dumb-bell-shaped figure, its division preceding that of the 

 cell (small Spirillum from Stylopyga). It is a living- 

 element — a morphological feature of each cell. In the 

 second type, there is a filament of a zig-zag or spiral form, 

 which also divides into two during cell-division (Spirillum 

 from Lacerta muralis). Thirdly and lastly, there is a 

 type of Spirillum whose characteristic morphological feature 

 is a system of granules scattered through the cell (Sp. 

 monospora, large Spirillum from Stylopyga). From a 

 consideration of these spirillar forms alone we could, with 

 considerable justification, reach the conclusion that these 

 three different types of structure represent three different 

 modifications of the nuclear apparatus — upon morphological 

 grounds. When the analogy of these structtires with the 

 nuclei of Cocci and Bacilli is considered, however, it appears 

 to me that only one logical deduction can be drawn, namely, 

 that the single spherule, the spiral filament, and 

 the chromidia of Spirilla are nuclei. 



Staining, again, gives results consistent with this inter- 

 pretation. 



I believe my n uclear interpretation of the various 

 structures discussed above is the only logical 

 intei'pretation which can be given to the facts 

 known to us at present. And of the accuracy of the 

 facts which I have recorded, I have not the slightest doubt. ^ 



' Owing to the fugitive nature of the staining methods which I have 

 frequently employed, it is now impossible to demonstrate many of my 

 preparations satisfactorily. I have therefore at various times demon- 

 strated my preparations to competent observers, in order that they 



