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periods varying from 10 days to a month. One solid media, however, have found them alive up to the end of this months. It is highly probable that, with some slight alteration in the constitution of the culture medium, their life in cultures would be
very much longer. In broth cultures the largest number of organisms is found after 3 days incubation; on solid media they
are most numerous
between the 15th and 20th day of
incubation.
The cultures were examined day by day,
both wet film preparations and smears,
stained with either Leishman's or
Giemsa's
method, being made.
Attached is a diagram upon which I have attempted to illustrate the forms which the organism assumes upon the culture media. The examination by means of wet film
preparations shows the different forms of the trypanosome only. The nucleus, centrosome,
and undulating membrane are
scarcely
visible, but the flagellum, which in most cases is long,
can usually be seen and is very distinct.