THE STRUCTURE OF TRYPANOSOMA LEWISI. 801 
The karyosome shows very considerable variations in some 
of the nuclei. In the first place it varies in size, being 
usually quite a minute granule, but sometimes very much 
larger. In the second place it varies in position, and instead 
of being central or sub-central it may be very excentric in 
position, even to the extent of being placed quite at one pole 
of the oval nucleus. Thirdly, the karyosome, usually single, 
may become double or multiple, apparently through a process 
of division or disruption. I have described elsewhere! such 
a process of budding on the part of the karyosome in the 
case of Trypanosoma granulosum, where the large size 
of the object makes the process easy to follow out in detail. 
The minuteness of T. lewisi makes it much more difficult to 
be quite certain what exactly takes place. Appearances can 
be found, however, which indicate clearly a process of division 
or budding from the karyosome (fig. 50), leading to the for- 
mation of two karyosomes, subequal or markedly unequal in 
size; the two bodies thus formed travel apart, and may place 
themselves at opposite poles of the nucleus (fig. 49). One or 
both of the karyosomes may undergo further disruption, 
apparently, so that im addition to a principal karyosome 
there are smaller granules present, not more than four in 
number in any case that I have observed (figs. 52, 53, 90) ; I 
feel, however, considerable doubt whether some of these 
smaller granules may not be, in most cases, granules of the 
intra-nuclear chromatin from which the stain has been insuffi- 
ciently extracted. In my preparations stained with Twort’s 
stain I find deviations from the condition with a single sub- 
central karyosome excessively rare; I have, however, seen 
in these preparations the condition with a double karyosome 
(fig. 86), and with a larger and two smaller karyosomes 
(fig. 90). 
Prowazek (1905, pp. 361-863) has sought to bring the 
various conditions of the karyosome under three processes, 
which he terms “autosynthesis,” ‘reduction,’ and ‘ par- 
thenogenesis.” In autosynthesis the karyosome is supposed 
+ «Proe. Zool. Soc.,’ 1909, pp. 21, 22, pl. V, figs. 78-93. 
