ssed over
its back. These we were told to look out for and to avoid them, if
possible. They occur only in certain districts and live in the deep
shade, near water. They also are day-biting insects, who do their biting
only between eleven o'clock in the morning and five o'clock in the
afternoon.

In the station there were a number of monkeys, upon which the fly was
being tried. They were in various stages of the disease, but it seemed
impossible to tell whether their illness was due to the sleeping
sickness germ or was due to tick fever, a common malady among monkeys.
In one of the rooms of the laboratory there were natives holding little
cages of tsetse flies against the monkeys, which were pinioned to the
floor by the natives. The screened cages were held close to the stomach
of the helpless monkey, and little apertures in the screen permitted the
fly to settle upon and bite the animal.

There are certain wide belts of land in Africa called the "tsetse fly
belts," where horses, mules and cattle can not live. These districts
have been known for a number of years, long before the sleeping sickness
became known. In the case of animals, the danger could be minimized by
keeping the animals out of those belts, but in the case of humans the
same can not be done. One infected native from a sleeping sickness
district can carry the disease from one end of the country to the other,
and when once it breaks out the newly infected district is doomed.
Consequently the British authorities are greatly alarmed, for by means
of this deadly fly the whole population of East Africa might be wiped
out if no remedy is discovered. It has not yet been absolutely proven
that East Africa is a "white man's country," and in the end it may be
necessary for him to give up hope of making it more than a place of
temporary residence and exploration.

We were also shown some ticks. They are the pests of Africa. They exist
nearly every place and carry a particularly malicious germ that gives
one "tick fever." It is not a deadly fever, but it is recurrent and
weakening. There are all kinds of ticks, from little red ones no bigger
than a grain of pepper to big fat ones the size of a finger-nail, that
are exactly the color of the ground. They seem to have immortal life,
for they can exist for a long time without food. Doctor Ward told us of
some that he had put in a box, where they lived four years without food
or water. He also told us of one that was se