CONTRIBUTIONS TO THE CYTOLOGY OP THE BACTERIA. 445 



most minute Bacilli, that I cannot avoid the impression that 

 all these diiJerent forms are really connected with one another. 

 This would be a point of great interest if it could be established, 

 but unfortunately no definite conclusion can be reached by 

 simply examining dead organisms.^ 



I found a number of individuals — of smaller size than the 

 large bacilli — which showed a very distinct nucleus of the 

 spirog-yra type. Some of these are shown in figs. 11 and 

 15. They measure about G fi in length, and are consider- 

 ably narrower than the large organisms which I call B. 

 saccobranchi. Each individual will be seen to contain 

 a characteristic nuclear filament of the spirogyva type. 



Some smaller forms, Avith a similar structure, are shown in 

 fig. 20. They measure about 3 jj. in length, and are much 

 narrower than the preceding forms : otherwise they are 

 closely similar. Nuclear filaments of various forms are 

 seen in each cell. 



Some still smaller organisms — 2 /n and less in length — are 

 depicted in fig. 19. In spite of their very minute size, 

 they show a nuclear filament with great distinctness. They 

 appear to possess a nucleus exactly like that of the spiro- 

 gyra forms of B. saccobranchi (fig. 2, etc.), but on a very 

 small scale. These are the smallest bacilli which I found in 

 the blood of S accobranchus. 



I would again em])hasise the fact that the various indi- 

 viduals depicted in figs. 2, 11, 20, and 19 ai-e organisms 

 selected on account of the difference in their sizes. Actually, 

 a number of intermediate-sized organisms of preciseh' similar 

 form were seen. 



I have added some figures of other organisms which were 

 of interest. The Bacillus shown in fig. 13 shows a nucleus 

 of a form which I observed in a few individuals. It is in the 



' If the organisms are all of one species, it follows that the name 

 B. saccobranchi sliould be given to all. As the matter is so doubtful, 

 however, I have restricted this name to the large forms only, though I 

 do not wish to imply thereby that the large forms are specifically 

 distinct. 



