308 H. B. FANTHAM. 



definitely distinguished as a sepnrate mass in these small 

 and young forms. 



Usually the shape of the principal chromatin mass is ovoid, 

 especially when occurring laterally. At other times, but less 

 commonly, it is round, as in the case of "polar" distribution. 

 Occasionally it is seen to be irregular (text-fig. 10 part). 

 The so-called blepharoplast is usually round, occasionally 

 ovoid. Rarely, the principal chromatin mass is in the form 

 of a curved rod (text-figs. 8 part, 16). 



Tliese different forms and appearances, more especially the 

 varying distribution of the chromatin masses, whether 

 '^ equatorio-lateral " or " polar,'^ may be explained, at any 

 rate in part, by regarding the parasite as viewed from 

 different aspects, as Christophers has pointed out in connection 

 with the Leishman-Donovan body. It may also be that, as 

 the parasite grows older, the blepharoplast becomes further 

 removed from the nucleus. The intra-corpuscular pyriform 

 parasites are almost certainly flattened to a greater or less 

 extent, as Nuttall and Graham-Smith (8, p. 639) have shown 

 in the case of the larger form, P. can is, from observations on 

 living blood. 



These observers also mention the occurrence of an achro- 

 matic halo around the nucleus or blepharoplast in some cases 

 (8, p. 592). I have very rarely seen this in P. bigcminum, 

 and then somewhat imj^erfectly (cf. text-fig. 9, part). 



On the whole, in the case of pairs of parasites, each member 

 of the pair is usually very like its fellow in size, shape, and 

 distribution of chromatin. Variations, however, occur (e. g., 

 text-figs. 9, 15), which ai-e comparatively few in proportion to 

 the large number of parasites examined. Reference has 

 already been made, incidentally, to these variations, whenever 

 it has been necessary to use the word " part" in referring to 

 a figure, thereby indicating variation among the individuals 

 of a pair. 



Minute isolated masses or dots of chromatin, other than the 

 three masses already mentioned, were rarely, if ever, seen 

 with certainty in these minute parasites. Further, no really 



