1910.] and T. rhodesiense as seen in Rats and G'uinea-pigs. 219 
while at the other end the blepharoplast (kinetonucleus) gradually migrates 
nearer the nucleus, and then the non-flagellar or posterior end of the original 
trypanosome is cast off, together with the remains of the flagellum. The 
rounded body, consisting of chromatin with a thin layer of cytoplasm, 
has then surrounded itself with a definite, very thin capsule (“cyst”). This 
process, a%seen under the microscope, is either the natural mode of formation 
of non-flagellate bodies in the internal organs or closely approximates thereto, 
as intermediate stages exactly similar in the formation of these bodies are 
seen in stained preparations of the heart, lungs, and spleen (Plate 15, 
figs. 1-5). ; | 
_ However, in the peripheral blood there occur rounded, oval or somewhat 
pyriform parasites (figs. 17-20), each with a single anterior flagellum. Such 
forms may, for convenience, be called rounding herpetomonad forms, as 
Herpetomonas passes through similar stages in assuming a rounded non- 
flagellate form. The rounded stages of Herpetomonas, thus formed, have 
been aptly termed post-flagellate stages by Captain Patton and by 
Dr. Annie Porter in their recent interesting researches on flagellates 
(Crithidia and Herpetomonas). The rounded, encapsuled stages of 
trypanosomes are post-flagellate stages. ‘That these rounded, post-flagellate 
forms are encapsuled in a thin membranous structure is shown by the 
fact that they resist maceration in water much longer than the trypaniform 
flagellates. 
The formation of post-flagellate bodies (figs. 2, 3, 5) is well seen in the 
lungs, whence they find their way in the blood stream to the spleen and bone 
marrow. 
The Structure of Latent Bodies. 
The post-flagellate (latent) stages of 7. gambiense and T. rhodesiense, 
already mentioned, have a relatively simple structure. The strictly latent 
or non-flagellate forms are usually oval in outline, and small, about 2 w to 4u 
in diameter (figs. 2-16). Less frequently are they quite rounded or spherical 
(fig. 14), while sometimes they are pyriform (figs. 25, 27, 29, 30). Internally 
there is a nucleus, which may show a karyosome, and beside the nucleus 
there is a blepharoplast or kinetonucleus (fig. 6)’ In some latent bodies. 
especially the smallest ones, the kinetonucleus may not be visible separately 
(figs. 11, 13-15), as it may be lying over the nucleus, or actually affixed 
thereto (figs. 2, 10). The juxtaposition of the nuclear bodies has been 
actually observed in some Romanowsky-stained specimens, after careful wet 
fixation (figs. 2,10). The relative positions of the nucleus and blepharoplast 
in rounding or rounded bodies may vary considerably. A small quantity of 
cytoplasm occurs in the latent bodies. ’ 
