How is it, you might ask me, that there are any natives left, if tropical Africa is so full of such beastly diseases as this? Is it that the native is naturally immune, or is it that the white man is of such a precious quality that he alone is attacked by these parasites and poisonous biting flies? The fact is that the native is affected also, and in childhood chiefly, so that the infant mortality in many native tribes is very high. And there is little doubt that repeated attacks of malaria in youth, if recovered from, do confer a kind of protection against attacks in adult life. But this is not the case with newly introduced disease; for the sleeping sickness that came to Uganda along the caravan routes from the Congo, has swept away fully a million of the natives along the shores of Lake Victoria Nyanza.
But the native has a sure sense of the unhealthiness of any locality, and one must be prepared for trouble when one notices that the native villages are built up on the hillsides. This was specially remarked by us on our long trek down the Pangani, and thus we were warned of the fever that lurked in the bright green lush meadows beside the water, and the "fly" that soon overtook our transport mules and cattle and the horses of General Brits' 2nd Mounted Brigade. At first we thought the columns of smoke along the mountain-sides beside the Pangani were signal fires for the enemy; but before long, when the roads were choked with victims of "fly" and horse-sickness, we realised the wisdom that induced the simple native to take his sheep and cattle up the hillsides and above the danger zone. When one spends only a short time in some native huts, it is quite clear how he escapes infection. For the floor is covered with a layer of wood ashes that is usually deadly to bugs and fleas and ticks and other crawling beasts; and the atmosphere is so full of wood smoke that the most enterprising mosquito or tsetse-fly would flee, as we do, choking from the acrid smoke. So the native fire that burns within his hut day and night not only serves to cook his food and to keep wild beasts away, but also supplies him with an excellent form of Keating's Powder for the floor and smoke to drive the winged insects from the grateful warmth of his fireside.
HORSE-SICKNESS
Lying beside the road with outstretched neck and a spume of white froth on nose and muzzle are the horses of the 2nd Mounted Brigade; with bodies swollen by the decomposition that sets in so rapidly in this sun, and smelling to high heaven, are the fine young horses that came so gallantly through Kahe some ten days ago. "Brits' violets" the Tommies call them, as they seek a site to windward to pitch their tents. "Hyacinths" they mutter, as the wind changes in the night, and drives them choking from their blankets, illustrating the truth of the South African "Kopje-Book" maxim, "One horse suffices to move a camp—if he be dead enough." For weeks after the Brigade passed through M'Kalamo the air was full of stench, and the bush at night alive with lions coming for the feast. For this is horse-sickness, the plague that strikes an apparently healthy horse dead in his tracks, while the Boer trooper hastily removes bridle and saddle and picks another horse from the drove of remounts that follow after. No time to drag the body off the road; so the huge motor lorries choose another track in the bush to avoid this unwholesome obstruction.
Horse-sickness takes ten short days to develop after infection, and the organism is so tiny that it passes through the finest filter and is ultramicroscopic. That means that it is too small to be recognised by the high power of an ordinary microscope. There was horse-sickness in the bush meadows beside the river near Kahe. Careless troopers watered their horses, after sundown, when the dew was on the grass and death lurked in the evening moisture where it had been absent in the dry heat of the afternoon.