388 A. A. MERLIN ON BACILLI OF BUBONIC PLAGUE. 



double forms, the longitudinal iSssure in the endoplasm is more 

 distinctly definable than the lateral. 



Fig. 2 is of a single form, in the same field as the preceding, 

 about the x4Wo^^ ^^ ^^ ^^^^ ^^^§- I^ ^^^e and arrangement of 

 its contents it is an exact facsimile of the lower component of 

 Fig. 1. The marked similitude of the internal features in these 

 two specimens seems to clearly lead to the conclusion that the 

 existing arrangement can be due to no fortuitous circumstance, 

 but represents a definite stage in the evolution of the cell. 



Fig. 3 shows a double form, the whole measuring longitudinally 

 about the yx^-fro*^ ^^ ^^ inch. The upper component exhibits a 



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I I 



very commonly existing variation in shape from its companion 

 cell. A longitudinal fissure is alone visible in the upper cell, the 

 lower having a tripartite arrangement of the contents. In this 

 specimen the endoplasm of the upper is united to that of the 

 lower cell, as shown in the figure — a somewhat rare feature. 



Figs. 5, 6, and 7 are drawn from other examples of the plague 

 bacillus, showing variation in form and arrangement of cell 

 contents. In some of these the points of attachment of the 

 flagella can be well seen, distinctly flagellated specimens being 

 frequently observable. 



Fig. 4 is a single plague coccus, about the ijo Jo o*^ ^^ ^^ ^^^^ 

 in diameter, exhibiting a well-marked cross partition of its 



