76 . THE INSECT WORLD. 



affected by it. Sudden changes ot 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 

 colour, 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. The stomach and 

 bowels are pale and empty, and the gall-bladder is distended with 

 bile. These symptoms seem to indicate, what is probably the case, 

 a poison in the blood ; the germ of which enters when the proboscis is- 

 inserted to draw blood. The poison-germ contained in a bulb at tlie^ 

 root of the proboscis, seems capable, although very minute in quantity,-, 

 of reproducing itself. The blood after death by Tsetse is very small Ij 

 in quantity, and scarcely stains the hands in dissection. . . . 



"The mule, ass, and goat enjoy the same immunity from die 

 Tsetse as man and game. Many large tribes on the Zambesi 

 keep no domestic animals except the goat, in consequence of th< 

 scourge existing in their country. Our children were frequenth 

 bitten, yet suffered no harm ; and we saw around us numbers o^ 

 zebras, buffaloes, pigs, pallas and other antelopes, feeding quietl] 

 in the very habitat of the Tsetse, yet as undisturbed 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 buftalo 

 and ox, the sheep and the 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 hill infested 

 by the insect, without allowing him time to graze, and though he only 

 remained long enough to take a view of the country and, catch some 

 specimens of Tsetse on the animal, in ten days afterwards the horse 

 was dead."'^ ■ . ' '. . ' 



* *' Missionary Travels and Researches in South Africa, "by David Livingslonc, 

 LL.D., D.C.L. V.%i,ctseq. London, John Murray, 1857. (The extract in the 



