1905.] Kala-Azar, etc., from Leishman- Donovan Bodies. 287 



shown in figs. 3 to 5 of the same line ; while in fig. 6 the division of the body 

 has just been completed, and in fig. 7 the micronuclei and fiagella of a still 

 adherent pair are dividing over again, thus showing how rapidly the 

 multiplication was taking place in this culture, for such forms were not 

 uncommonly seen in it. 



In my earlier cultures the flagellated pairs were nearly always found in 

 pairs only, although rarely three or four might be seen side by side. In the 

 much more abundant development of flagellates in the acid culture medium, 

 however, considerably larger masses, forming beautiful rosettes, with the 

 fiagella crossing each other in the centre, were seen in large numbers, and it 

 is easy to understand how they may be formed by the rapid multiplication 

 just described. Thus fig. 6 of Line IV shows a small group of flagellates 

 which is remarkable for including nearly all the stages of division in a single 

 clump, while fig. 9 shows the commencement of the formation of a rosette by 

 the rapidly dividing flagellates pushing each other round to form a semi- 

 circular mass, and in fig. 12 is shown a small, but complete, rosette, several 

 of the forms in which are undergoing further subdivision. In this stage the 

 contents of the eosin bodies frequently becomes protruded, as I have 

 previously noted, and it accumulates round the fiagella, helping to bind the 

 forms together into the rosette shape. Next, the individual organisms 

 elongate, and at the same time become narrower, and the rosette then 

 commences to break up, in consequence of the increasing motility of the 

 fiagella, and some now separate from the mass in pairs or single forms as 

 indicated in fig. 11, and in this manner the free swimming forms shown in 

 Lines IV and V of the plate are produced. In fresh specimens these are 

 very active, the single ones in particular threading their way rapidly among 

 the red corpuscles, and on reaching an open space, dart about in such a 

 manner as to leave no doubt in the mind of the observer that the object of 

 this remarkable development and extraordinary increase in size is to endow 

 the motionless human stage of the organism with the power of loco- 

 motion required in some period of its extra-corporeal existence. 



The Nature of the Fully Developed Flagellate Form of the Orga/ainn. 



When I first obtained the development of the flagellated stage, I thought 

 them to be young trypanosomes which had not yet formed an undulating 

 membrane. In support of this possibility, the recent observations of Xovy 

 and MacNeil(12) on the culture of trypanosomes of birds on blood agar are 

 of great interest, for they obtained forms, separate and in rosettes, most 

 closely resembling those shown in the plate accompanying the present paper, 



