472 
Placental blood. —Living flagellates, few rounded bodies. 
Thirteen embryos. —Serous fluid contained a very few 
trypanosomes. 
Embryonic liver. — No flagellate trypanosomes seen. 
From counts of the number of trypanosomes in the peripheral 
blood daily, and from examination of carefully prepared smears of 
organs, it is found that latent bodies are most numerous when the 
flagellate parasites are few. If inoculated animals be killed at 
these periods, very few flagellate trypanosomes are found in the 
spleen and bone marrow (see preceding tables), but many latent 
bodies are present in those organs, while rounding forms are seen 
especially in the lungs. 
In the peripheral blood, on the upward slope of the curve 
representing the numbers of the parasites from day to day, the 
parasites increase in numbers by longitudinal division to a 
maximum. At or about this period the formation of rounded or 
latent bodies begins, and takes place especially in the internal 
organs. 
If rounded (latent) bodies, derived from the internal organs ol 
an infected rat, be placed in warm fresh blood drawn from a 
normal, uninfected rat, then growth of some of the rounded bodies 
towards the flagellate trypaniform stage can be seen under the 
microscope, as is detailed in a subsequent section of this paper. 
Fiv e guinea-pigs (three inoculated with T. rhodesiense and two 
with T. gambiense ), dying in various stages of trypanosomiasis, 
wcie carefully examined, and fresh preparations and smears ol 
their internal organs were made. Rounding and rounded 
forms of try’panosomes were seen, just as in infected rats. 
Needless to say, a very' careful examination of the internal 
organs of normal (uninfected) rats and guinea-pigs was made for 
the purposes of comparison and control. 
the formation of latent bodies from 
FLAGELLATE TRYPANOSOMES 
I his is diagrammatically represented in text-fig. i, in which 
1 01 niation of a rounded body' from a living trypanosome was 
reived under the microscope in a drop of blood and lymph from 
