NOTES ON SrOROZOA — III. 
197 
little more than a nurozoite/ has a single large kai'yosonie 
placed quite at one side of the general nuclear substance; 
the latter is finely granular in character, and does not stain 
deeply, the granules beiug fairly uniform in size and 
appearance. More frequently a rather later condition or 
phase is found, in wliich there are two karyosomes, generally 
at opposite sides of the principal nuclear mass; these two 
karyosomes are usually more or less unequal in size, and 
neither is so large as when there is only one. I have been 
much exercised in regard to the question of the true situa- 
tion of these karyosomes. In nearly all the individuals 
a well-marked clear zone, which in some cases is relatively 
wide, surrounds both the general nuclear substance and the 
karyosomes (or karyosome). Is this clear zone to be con- 
sidered merely as a shrinking-space, separating the whole of 
the nuclear orgauellm from the general cytophism of the 
parasite, or is this area really within, and therefore a part of, 
the nucleus, the limit or border of which is on the outer side 
of the clear area and in contact with the edge or margin of 
the surrounding cytoplasm ? In the former case, of course, 
the karyosomes would be actually extra-nuclear; in the latter 
they would be within the nucleus, but excentrically placed, 
near the periphery. After some liesitation I have come to the 
conclusion that the latter view is the correct one, and that the 
pale, clear area really constitutes the peripheral region of the 
nucleus. In the case of most individuals I have found it 
almost impossible to satisfy myself of the existence of a definite 
membrane, bordering this zone externally, as distinct from the 
edge or margin of the surrounding cytoplasm itself ; and the 
same difficulty has presented itself apparently to other 
observers, if one may judge from certain of their figures (e.g. 
Siedlecki’s fig. 17 and Jollos’ figs. 22 and 28). Moreover, 
the limit of the centrally situated, uniformly granular, 
' The earliest cliaiige in the condition of the karyosome, namely its 
<livision into two, may even take place before the fully formed merozoite 
has been liberated from the “ barillet ” of which it has constituted a 
segment. 
