THE CHROMATIN MASSES OF PIUOPLASMA BIGEMINUM. 309 



definite cases of the entire absence of chromatin from a 

 pai'asite were encountered. 



Regarding the rehitive positions of the nucleus and ble- 

 pharoplast, it may be noted that although the latter is fairly 

 often seen in close proximity to the former^ and even con- 

 nected with it by loose chromatin, yet I have never seen the 

 blepharoplast actually on the nucleus, or directly budded off 

 from it, as stated by Liihe in P. canis. Also, the relative sizes 

 of these two chief chromatin masses can only be determined by 

 careful differentiation and sharp focussing from the granular 

 cytoplasm, sometimes surrounding one or both of them. 



(/3) The Chromatin in Pairs of Ovoid Intra- 

 corpuscular Parasites. 



Pairs of strictly ovoid parasites^ in which each 

 member of the pair is truly ovoid, are rare. Under this 

 heading it will be convenient to consider cases of pairs of 

 parasites where one member is strictly ovoid in shape while 

 the other is more or less so, yet still shows something of a 

 pyriform contour and may be rather fusiform (text-fig. 24), 

 for the gradation in shape between the two forms is pro- 

 gressive. Such pairs of parasites merit separate consideration 

 as a group after the large number of more strictly pyriform 

 types already discussed. 



In these cases we have the same broad distribution of 

 chromatin as before. The '^ equatorio-lateral ^' arrangement 

 of the nucleus and so-called blepharoplast preponderates. 

 This distribution of the chromatin, together with the ovoid 

 contour of the micro-organism, recalls, superficially, the 

 appearance of the Leishman-Donovan body. 



A few interesting forms showing the connecting bridge of 

 chromatin between the nucleus and blepharoplast were seen 

 (text-fig. 20 part). Three masses of chromatin in each para- 

 site of a pair are shown in text-fig. 19, which masses appeared 

 stained about the same colour and intensity, while the mass 

 which might probably be termed the blepharoplast was in 



