146 E. A. MLNCHIN AND H. M. WOODCOCK. 



already quite evident, from figures published during the last 

 year or two, since the use of the iron-hsematoxylin stain 

 became more general, that the trophonucleus is in the main 

 constituted on the same plan, having most of its chromatin 

 associated with a definite karyosomatic body. Besides Miss 

 Robertson (17), Minchin has shown this to be the case both 

 in various fish-trypanosomes (13) and also in T. lewisi (14). 

 We may mention that during the progress of our work at 

 Rovigno wo have obtained a similar result in the case of the 

 trypanosomes in the little owl; and we see that recently 

 Roseubusch has published figures (20) of cultural forms of 

 these trypanosomes (which he calls " Hasmoproteus 

 noctuae" and " Leucocytozoon ziemanni") showing 

 this same nuclear structure. 



Further, we are inclined to think that in many cases the 

 minute details of the karyosome will be found to be similar, 

 that is to say, as regards the tendency of the chromatin to 

 be located at the periphery of the plastinoid basis, and the 

 presence in the centi-al, clearer zone of a definite granule. 

 Of course, nuclei with a large karyosome may be expected to 

 show this more distinctly than those with a very small karyo- 

 some (such as, for example, T. lewisi.) One of us (H. M. W.) 

 has several times observed, in Giemsa preparations of a 

 trypanosome of the chafiinch,^ an appearance of the nucleus 

 quite similar to that in fig. 37, namely, a conspicuous granule 

 occurring in the centre of a clear zone in the middle of the 

 nucleus ; and the interpretation of the whole appearance is 

 doubtless also the same. It is interesting to note that some 

 years ago Laveran and Mesnil, in their account of certain 

 trypanosomes of fishes (7), published a figure of T. remaki, 

 of the pike, which showed the same nuclear appearance. 

 We remember thinking this unusual at the time, as it was 

 quite difi^erent from the uniform granular character which the 

 nucleus was generally described as possessing. 



These finer details of the karyosome are best revealed, 



' It is hoped to publish an account of this pai-asite, and of othei*s in 

 the chaffinch, very shortly. 



