COXTRIBUTIONS TO THE CYTOLOGY OF THE BACTERIA. 433 



more or less spherical^ nucleus-like masses (figs. 85, 88^ 90). 

 Some individuals possess tliree or four of these structures 

 (fig. 85), Avhilst others — usuall}' much shorter — possess but 

 one (fig. 88). These "nuclei^' bear a strong resemblance to 

 the nucleus-like spore-rndiments of B. flexilis and similar 

 forms, and it is possible that they are of a similar nature. 

 Spores, however, are not present in any of the organisms. 



A third modification of the chromatin which I found is that 

 shown in fio-.s. 86 and 87. It will be seen that the cliromatic 

 elements are neither in the form of diffuse chromidia, nor in 

 the form of aggregated ''nuclei," but in the form of a broken 

 spiral filament. In no single case did I observe a complete 

 filament like that of B. spirogyra. In the organism 

 depicted in fig. 86 the chromatin is disposed as follows : a 

 dumb-bell-shaped figure, two nucleus-like masses, and a short 

 spiral filament with enlarged ends. Fig. 87 shows a single, 

 nucleus-like mass, a short spiral filament, a small chromatin 

 rodlet^ a small dumb-bell figure, and a second more drawn 

 out spiral filament. 



After examining all these different forms of nuclear appa- 

 ratus, my impression is that they are different stages in the 

 life-history which are connected with one another in the 

 following way. The chromidial form (fig. 89) becomes con- 

 verted into the "nucleated" form (fig. 85) by the aggrega- 

 tion of chromatin at various centres ; this nucleated form then 

 gives rise to the form with the spiral filaments (fig. 87) owing 

 to the drawing out of the nuclei by a process similar to that 

 seen occasionally in the division of the nuclei in Micrococci 

 (compare fig. 52). This is very strongly suggested in the 

 organisms shown in figs. 86 and 87. 



That this interpretation of the appearances is correct I can- 

 not, of course, be certain. But the appearances are so sug- 

 gestive that I cannot refrain from making the suggestion that 

 in this organism we have a clue to much that is obscure in 

 tlie morphology of the bacterial nucleus. It seems to me 

 highly probable that in this organism three different arrange- 

 ments of the chromatin — chromidia, spherical nucleus, and 



