Not content with a passing attack, a South American gadfly (Œstrus hominis) deposits its eggs under the human skin, where the larvæ continue for six months. If disturbed, they penetrate deeper, and produce troublesome ulcers, which sometimes even prove fatal. Thus, in tropical America, we find the same insect tribe which plagues our oxen and horses, and reduces the northern reindeer to desperation, settle on man himself, and render even the lord of creation subject to its power.
The Chegoe, Pique, or Jigger of the West Indies (Pulex penetrans) is another great torment of the hot countries of America.
It looks exactly like a small flea, and a stranger would take it for one. However, in about four and twenty hours he would have several broad hints that he had made a mistake in his ideas of the animal. Without any respect for colour, it attacks different parts of the body, but chiefly the feet, betwixt the toe-nails and the flesh. There it buries itself and causes an itching, which at first is not unpleasant, but after a few days gradually increases to a violent pain. At the same time a small white tumour, about the size of a pea, and with a dark spot in the centre, rises under the skin. The tumour is the rapidly growing nest of the chegoe, the spot the little plague itself. And now it is high time to think of its extirpation, an operation in which the negro women are very expert. Gently removing with a pin the skin from the little round white ball or nest, precisely as we should peel an orange, and pressing the flesh all round, they generally succeed in squeezing it out without breaking, and then fill the cavity with snuff or tobacco, to guard against the possibility of a fresh colony being formed by some of the eggs remaining in the wound. New comers are particularly subject to these creatures. Waterton, who by practice appears to have become very expert in eradicating chegoes’ nests, once took four out of his feet in the course of the day, and a negress extracted no less than eighty-three out of Richard Schomburgk’s toes in one sitting. ‘Every evening,’ says the venerable naturalist of Walton Hall, ‘before sundown, it was part of my toilet to examine my feet and see that they were clear of chegoes. Now and then a nest would escape the scrutiny, and then I had to smart for it a day or two after. A chegoe once lit upon the back of my hand: wishful to see how he worked, I allowed him to take possession. He immediately set to work head foremost, and in about half an hour he had completely buried himself in the skin. I then let him feel the point of my knife, and exterminated him.’
If the prompt extraction of the chegoes’ nests is neglected, the worm-like larvæ creep out, continue the mining operations of their parent, and produce a violent inflammation, which may end in the mortification of a limb. It not unfrequently happens that negroes from sheer idleness or negligence in the first instance have been lamed for life and become loathsome to the sight. In such a state, these miserable objects are incurable, and death only puts an end to their sufferings.
A still more dangerous plague, peculiar to the coast of Guinea and the interior of tropical Africa, to Arabia, and the adjacent countries, is the Filaria medinensis of Linnæus. This dreaded worm comes to the herbage in the morning dew, from whence it pierces the skin, and enters the feet of such as walk without shoes, causing the most painful irritation, succeeded by violent inflammation and fever. The natives extract it with the greatest caution by twisting a piece of silk round one extremity of the body and withdrawing it very gently. When we consider that this insidious worm is frequently twelve feet long, although not thicker than a horse-hair, we can readily imagine the difficulty of the operation. If unfortunately the animal should break, the part remaining under the skin grows with redoubled vigour, and frequently occasions a fatal inflammation.
One of these most unwelcome intruders once entered Dampier’s ankle. ‘I was in great torment,’ says this entertaining traveller, ‘before it came out. My leg and ankle swelled, and looked very angry, and I kept on a plaster to bring it to a head. At last, drawing off my plaster, out came three inches of the worm, and my pain abated. Till that time I was ignorant of my malady, and a gentleman at whose house I was took it for a nerve; but I knew well what it was, and presently rolled it up on a small stick. After this I opened the place every morning and evening, and strained the worm out gently, about two inches at a time—not without some pain—till I had at length got it out.’
Among the plagues of Guiana and the West Indies we must not forget a little insect in the grass and on the shrubs, which the French call bête-rouge. It is of a beautiful scarlet colour, and so minute that you must bring your eye close to it before you can perceive it. It abounds most in the rainy season. Its bite causes an intolerable itching, which, according to Richard Schomburgk, who writes from personal experience, drives by day the perspiration of anguish from every pore, and at night makes one’s hammock resemble the gridiron on which Saint Lawrence was roasted. The best way to get rid of the plague is to rub the part affected with lemon-juice or rum. ‘You must be careful not to scratch it,’ says Waterton. ‘If you do so and break the skin, you expose yourself to a sore. The first year I was in Guiana the bête-rouge and my own want of knowledge, and, I may add, the little attention I paid to it, created an ulcer above the ankle which annoyed me for six months, and if I hobbled out into the grass, a number of bête-rouges would settle on the edges of the sore and increase the inflammation.’
The blood-sucking Ticks are also to be classed among the intolerable nuisances of many tropical regions. A large American species called Garapata (Ixodes sanguisuga) fixes on the legs of travellers, and gradually buries its whole head in the skin, which the body, disgustingly distended with blood, is unable to follow. On being violently removed, the former remains in the wound, and often produces painful sores. The Indians returning in the evening from the forest or from their field labour generally bring some of these creatures along with them, swollen to the size of hazel nuts.
Though countless hosts of ticks infest the Ceylonese jungle, though mosquitoes without number swarm over the lower country, yet the land-leeches which beset the traveller in the rising grounds are a still more detested plague. ‘They are not frequent in the plains,’ says Sir E. Tennent, ‘which are too hot and dry for them; but amongst the rank vegetation in the lower ranges of the hill-country, which is kept damp by frequent showers, they are found in tormenting profusion. They are terrestrial, never visiting ponds or streams. In size they are about an inch in length, and as fine as a common knitting needle, but capable of distention till they equal a quill in thickness and attain a length of nearly two inches. Their structure is so flexible that they can insinuate themselves through the meshes of the finest stocking, not only seizing on the feet and ankles, but ascending to the back and throat, and fastening on the tenderest parts of the body. The coffee planters who live amongst these pests are obliged in order to exclude them, to envelope their legs in “leech gaiters,” made of closely woven cloth.
‘In moving, the land-leeches have the power of planting one extremity on the earth and raising the other perpendicularly to watch for their victim. Such is their vigilance and instinct that, on the approach of a passer-by to a spot which they infest, they may be seen amongst the grass and fallen leaves, on the edge of a native path, poised erect, and preparing for their attack on man and horse. On descrying their prey they advance rapidly by semicircular strides, fixing one end firmly and arching the other forwards, till by successive advances they can lay hold of the traveller’s foot, when they disengage themselves from the ground and ascend his dress in search of an aperture to enter. In these encounters the individuals in the rear of a party of travellers in the jungle invariably fare worst, as the leeches once warned of their approach congregate with singular celerity. Their size is so insignificant, and the wound they make so skilfully punctured, that the first intimation of their onslaught is the trickling of the blood, or a chill feeling of the leech when it begins to hang heavily on the skin from being distended by its repast. Horses are driven wild by them, and stamp the ground in fury to shake them from their fetlocks, to which they hang in bloody tassels. The bare legs of the palankin-bearers and coolies are a favourite resort, and their hands being too much engaged to be spared to pull them off, the leeches hang like bunches of grapes round their ankles; and I have seen the blood literally flowing over the edge of a European’s shoe from their innumerable bites. In healthy constitutions the wounds, if not irritated, generally heal, occasioning no other inconvenience than a slight inflammation and itching; but in those with a bad state of body, the punctures, if rubbed, are liable to degenerate into ulcers, which may lead to the loss of limb or of life. Both Marshall and Davy mention that, during the march of the troops in the mountains, when the Kandyans were in rebellion, in 1818, the soldiers, and especially the Madras Sepoys, with the pioneers and coolies, suffered so severely from this cause that numbers of them perished.’