erienced the slightest injury
from them ourselves, personally, although we lived two months in their
HABITAT, which was in this case as sharply defined as in many others,
for the south bank of the Chobe was infested by them, and the northern
bank, where our cattle were placed, only fifty yards distant, contained
not a single specimen. This was the more remarkable, as we often saw
natives carrying over raw meat to the opposite bank with many tsetse
settled upon it.

The poison does not seem to be injected by a sting, or by ova placed
beneath the skin; for, when one is allowed to feed freely on the hand,
it is seen to insert the middle prong of three portions, into which the
proboscis divides, somewhat deeply into the true skin; it then draws it
out a little way, and it assumes a crimson color as the mandibles come
into brisk operation. The previously shrunken belly swells out, and,
if left undisturbed, the fly quietly departs when it is full. A slight
itching irritation follows, but not more than in the bite of a mosquito.
In the ox this same bite produces no more immediate effects than in man.
It does not startle him as the gad-fly does; but a few days afterward
the following symptoms supervene: the eye and nose begin to run, the
coat stares as if the animal were cold, a swelling appears under the
jaw, and sometimes at the navel; and, though the animal continues to
graze, emaciation commences, accompanied with a peculiar flaccidity
of the muscles, and this proceeds unchecked until, perhaps months
afterward, purging comes on, and the animal, no longer able to graze,
perishes in a state of extreme exhaustion. Those which are in good
condition often perish soon after the bite is inflicted with staggering
and blindness, as if the brain were affected by it. Sudden changes of
temperature produced by falls of rain seem to hasten the progress of the
complaint; but, in general, the emaciation goes on uninterruptedly for
months, and, do what we will, the poor animals perish miserably.

When opened, the cellular tissue on the surface of the body beneath the
skin is seen to be injected with air, as if a quantity of soap-bubbles
were scattered over it, or a dishonest, awkward butcher had been trying
to make it look fat. The fat is of a greenish-yellow color and of an
oily consistence. All the muscles are flabby, and the heart often so
soft that the fingers may be made to meet through it. The lungs and
liver partake of the disease.