82 
THE TSETSE POISOH. 
Chap. IY. 
terruptedly for months, and, do what we will, the poor animals 
perish miserably. 
^Vhen opened, the cellular tissue on the surface of the body 
beneath the skin is seen to be injected with ah’, 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 colour and of an oily consistence. All the 
muscles are liabby, and the heart often so soft that the fingers 
may be made to meet through it. The lungs and liver partake 
of the disease. The stomach and bowels are pale and empty, 
and the gall-bladder is distended with bhe. 
These symptoms seem to indicate what is probably the case, a 
poison in the blood ; the germ of wliicli enters when the proboscis 
is inserted to draw blood. The poison-germ, contained in a bulb 
at the root of the proboscis, seems capable, although very minute 
in quantity, of reproducing itself, for the blood after death by 
tsetse is very small in quantity, and scarcely stains the hands in 
dissection. I shall have by and by to mention another insect, 
vdiich by the same operation produces in the human subject both 
vomiting and purging. 
The mule, ass, and goat enjoy the same immunity from the 
tsetse as man and the game. Many large tribes on the Zambesi 
can keep no domestic animals except the goat, in consequence 
of the scourge existing in them country. Our cliildren were 
frequently bitten, yet suffered no harm; and we saw around us 
numbers of zebras, buffaloes, pigs, pallahs and other antelopes, 
feeding quietly in the very habitat of the tsetse, yet as undis¬ 
turbed by its bite as oxen are when they first receive the fatal 
poison. There is not so much difference in the natures of the 
horse and zebra, the buffalo and ox, the sheep and antelope, as to 
afford any satisfactory explanation of the phenomenon. Is a man 
not as much a domestic animal as a dog ? The curious feature 
in the case, that dogs perish though fed on milk, whereas 
the calves escape so long as they continue sucking, made us 
imagine that the mischief might be produced by some plant in 
the locality, and not by tsetse; but Major Vardon, of the Madras 
Army, settled that point by riding a horse up to a small lull 
infested by the insect without allowing him time to graze, and, 
tliough he only remained long enough to take a view of the 
