45 « 
the bone marrow, and do not necessarily degenerate there. They 
persist in such situations in very large numbers, and each consists of 
a flattened nucleus with an intra-nuclear centrosome. There is also 
a vesicle attached to the nucleus, and the whole nuclear apparatus is 
surmounted by a thin film of protoplasm, figs. 27, 28. 
At the periods when there are no trypanosomes to be found in the 
blood, these peculiar latent bodies are all the evidence of the existence 
of the parasites in an infected animal to be detected microscopically. 
At the period of the infection when a few parasites begin to 
reappear in the blood, it is possible to still find numbers of latent 
bodies in the spleen, and in the bone marrow, wherein the intra¬ 
nuclear centrosome has divided into two, fig. 28. 
Again, at this period it is possible to find forms in which one-half 
of the dividing intra-nuclear centrosome has passed out of the nucleus, 
fig- 28, forming an extra-nuclear centrosome. Still further, at a 
later period, we find forms in which a short flagellum has grown from 
e extra nuclear centrosome, and these bodies subsequently appear 
gradually transfoim themselves into small trypanosomes in the 
manner represented in figs. 28 to 32. 
As the latent bodies are gradually transformed into small trypano- 
somes, the number of these bodies in the spleen and bone marrow 
diminishes, but it appears to be the case that a proportion of what are 
apparently latent bodies never really develop into trypanosomes and 
thT^hT t0gether ’ ° r ’ in other w °rds. ^at only a proportion of 
sumv I" ar£ Under Clrcumstan ces above described capable of 
too com ' r negatlVe Peri ° d ' ^ ° nCe ”° re f°™ing themselves 
into complete trypanosomes. 
havJhIthert?b S Wh ‘ C M WB haVe n ° W deSCnbed are aU those which we 
of the infection Tn" rats 6 ^ “ reIatlon to the succeeding stages 
encountered dlring" d^erent ^ Changes might have bee " 
although we have had the ■ Pen ° ds ° f the da y ^ night, but 
tion continuouslv at nil p . ai ^ sites ln various animals under observa- 
several days L ° f ** CUne of Action throughout 
discernible. Howevw. 1 t was 7 'Tu™ nocturnal . aIteration was 
number of parasite* 1 ■*’ ° Und t ^ lat t ^ le ra pid diminution of the 
So fa T he at T anably t0 ° k P lace between 2 and 5 ,, 
the above observations upon the life cycle of the 
