286 Dr. L. Rogers. Development of Hepatomonas of [Oct. 16, 



of the smaller oval forms, and but few flagellated ones as in alkaline blood, 

 in the acid medium the great majority of the parasites will be found in 

 nearly the same stage on any given day, and nearly all become flagellated 

 after a few days. The sequence of events during the first two days is 

 the same as I have already described, (8) and they are well shown in the 

 first two lines of the accompanying plate — all the figures in which have been 

 drawn to the uniform scale of 1500 diameters magnification, with the aid of 

 a camera lucida. Line I shows the parasites seen in a film of spleen blood 

 made at the time it was obtained, and consequently before any development 

 had taken place. After incubation for two days at 22° C. the forms shown 

 in Line II were present, figs. 1 and 2 showing considerable enlargement, 

 especially of the macronucleus and protoplasm of the body. Figs. 3 and 4 

 also show the earliest appearance of the eosin-staining body, which is repre- 

 sented as a clear space in the drawings, but is of a rosy-pink colour 

 with Romanosky's stain, and quite distinct from the vacuoles, the latter 

 being indicated by the more lightly shaded portions of the protoplasm. 

 It will also be noted that from the first the micronucleus, or blepharoplast, 

 is closely attached to the eosin body (called by Leishman " flagellar body "). 



Further, on the second day in this acid culture a few of the early 

 flagellated forms shown in figs. 7 and 8 of Line II were also seen, although 

 they do not usually appear in alkaline cultures until at least the third day, 

 while just antecedent to this stage are the forms shown in figs. 5 and 6 

 of the same line, illustrating commencing elongation and division by fission, 

 and it will be observed that in these the eosin body is passing up to the 

 anterior end of the organism from which the flagellum arises, and is carrying 

 the micronucleus with it. In my earlier description I suggested that the 

 double elongated forms shown in fig. 6 of this line might possibly represent 

 a form of conjugation preparatory to the development of the flagellated 

 stage of the organism, but further study of a much larger amount of material 

 has convinced me that they are only fission forms, as I have been unable to 

 make out any reduction in the number of chromosomes in the macronucleus 

 during the process. 



Hie Mode, of Division of tJie Flagellated Forms and, the Formation of Rosettes. 



In Line III of the plate are represented the different stages of division of 

 newly formed flagellated bodies. Figs. 1 and 2 show that the micronucleus 

 and flagellum first divide, just as in trypanosomes, and next the macro- 

 nucleus divides in turn, and a clear line appears in the length of the 

 organism, indicating commencing division of the protoplasm of the body, as 



