MOSQUITO MURDER OF MANKIND.

Pelorus Guardian and Miners' Advocate., Volume 30, Issue 17, 1 March 1918, Page 2

MOSQUITO MURDER OF MANKIND.

VUiCOVEKY THAT MAY PROLONG RACES.

History teaches that the mosquito Saa been the pest of mankind from the earliest times. Science has recently demonstrated that the mosquito can be exterminated. Is the world ready to co-operate in the gigantic . hut entirely possible, task of ridding the earth of this nuisance ?

Presumably there were mosquitoes in the Garden of Eden. They existed on the earth millions of years before the first human beings arrived—-a fact, proved by the discovery of fossil specimens preserved in the strata of rocks. One species of the Tertiary Age (happily extinct) was much bigger than any modern mosquito. Naturalists have named it Culex damnatorum, or “gnat of the damned.”

According to Herodotus, the ancient historian, there were prodigious numbers of mosquitoes in Egypt in the daj'S of the Pharaohs. They were such an affliction, indeed, that rich men built tall towers and slept on the roofs thereof—the habit of these insects being not to fly more than thirty feet or so above the ground ; though in modern houses they comnonly climb from floor to floor or go »p in the lifts, even to the top of a skyscraper. “The glory of what was Greece,” was not destroyed by war. It was wiped out by mosquitoes. Such at all events is the belief accepted by moitem historians. Greece, in prehistoric times, was peopled by succor- ' ive waves of invaders from the north —men of light complexion and fair hair, who built up the wonderful civilisation which in some respects las not been surpassed, if equalled.

'*, This civilisation reached its climax ;n the time of Pericles. At that period Greece was at the height of her '-lory. Her fertile valleys were thickly peopled ; her commerce and agriculture were highly prosperous ; her military renown (she had conquered oth Persia and Egypt) was such as fc;o fulfil the utmost ambition of a 'warlike race vigorous and well train'd in arms.

' Then—almost suddenly, it would ?3eem—came the debacle. Greece and ■} sr glory went to pieces. Her empire ?*nd her civilisation were destroyed. ,'3ven her people vanished from the ecene ; for the Greeks of to-day, ’largely Slavic in origin, dark-haired ?and dark-slrinned, are certainly not descendants of those early settlers. . became of them ? Did the .Irnosquitoes eat them up ? Hardly *:hat, but the result was the same, "fhe mosquitoes distributed malaria, 'sapping the energies of the once formidable race, destroying the rural population, and killing the young children.

Whence came the malaria ? The 'answer is that it must have been introduced from some other region. This once accomplished, the infection 'was spread among the mosquitoes, which distribted it far and wide among the people by their bites. The .air-haired race, having inherited no constitutional resistance to the disuse (for lack of exposure to it through generations) readily succumbed to its attacks.

Greece to-day is one of the most malaria-cursed countries in the world. The malady has made vt and kept it a back-number among modern nations. Children are enfeebled by it irom early infancy. Industry is to a great extent paralysed by the disease and the development of agricultural land is retarded, because the workers, shaken by chills and burned by fever, •are incapacitated during a large part of the year. The same fate, from the same cause, seems to have overtaken ancient Rome. Not the growth of excessive luxury, nor yet the might of barbarian invaders (says the modern historian), accomplished the disintegration and eventual destruction of that colossal empire. The malariacarrying mosquito did it. ; To-day the Campagna (in the midst ,of which Rome is situated) is so “rightfully malarial that its inhabitants all suffer from chills and fever. The malaria in that region, too, is of a very malignant type. It is the dreaded “Roman fever, ’’ which often .Sills its victims within a few days •after they are bitten by infected mosquitoes. To the average person all mosTUitoes look alike. As a matter of fact, however, the various species differ as much in structure and appearance as do the pig and the dog, the teer, and the horse. Some are giants ; others are relative pigmies. In the pigmy class is the yellow fever mosquito. Like the malaria mosquito, it is entirely harmless (save for the annoyance it causes) unless it Ufis become infected by biting a person sick with the disease.

The yellow fever mosquito is easily recognised. It is when viewed under :he microscope, a beautiful insect, strikingly marked, with a silvery--.vbite, lyre-shaped pattern on its thorax, with stripes on its abdomen and legs handed in black and ■ vhite.

A common house mosquito in some 'atitudes is Culex pipiens—also known; as the “rain-barrel mosquito.” Like the yellow fever carrier of the tropics, it' seeks human companionship ; it is as much an intimate companion of mankind as the rat, though equally unwelcome. It is said to be the carrier of the frightful malady called "elephantiasis.” This disease is caused by a

minute parasitic worm. If the insect happens to have bitten a sufferer from elephantiasis , ! t is likely to intronuce the worm into the blood of the next person it bites. The worm multiplies

m enormous numbers in the blood, and making its way into the lymph channels, chokes them up, the result being a huge and permanent swelling (resembling an overgrowth) of one or more of the limbs.

Another very common species of mosquito, Culex fatigans, is the sole carrier of “break-bone fever," otherwise known as "dengue.” It is an l acutely epidemic disease, often spreadin with such rapidity as to be termed “explosive.” The symptoms are high fever, terrible pains in the bones, and an eruption resembling that of scarlet fever. Though not often fatal, it disables the victim for a long period. If one would escape mosquitoes and the dangers they bring, where should one go ? The answer is that no place in the'world is free from these pestiferous enemies of mankind. Many species seem to be cold-proof ; some will breed actually in pools of melting ice.

Has the mosquito a natural enemy whose services can be 6nlisted to fight the mosquito ? There is at least one such enemy of the mosquito—the bat. The bat is now being tested as a mosquito remedy. According to Dr. Charles Campbell, of San Antonio, Texas, the bat feeds almost exclusively upon mosquitoes. Wherever bats are plentiful malaria is virtually unknown, because they consume the mosquitoes before the insects have time to develop and do harm. When the bats are properly provided for they increase very rapidly in number, and a municipal rooet, in addition to its hygienic value, becomes a little gold mine, on account of the high-grade fertiliser it produces. This fertiliser, called bat guano, is always in demand and finds a ready market. It has been estimated that in India the mortality from malaria is 1,130,C00 human beings annually. In Greece, with a population of only 2,500,000 there are 900,000 eases of this disease every year. These figures give a fairly good idea of the deadly work of the mosquito—for the prevalence of malaria depends largely upon the activities of this prolific carrier. Before Dr. Campbell erected his experimental bat roost on the shore of a swampy lake, the mosquitoes were so abundant that they actually drove the men from their work in the fields near by. They covered the bodies of the work animals and drove them to such desperation that it was next to impossible to get satisfactory work from these tormented animals. All the farm animals were similarly tortured by these insects, and their productive powers greatly diminished. Shortly after the bat roost had been put into operation the mosquitoes disappeared entirley, and no longer disturb the comfort of man or beast, and malaria is no more.

Nature has provided the bat with remarkable vowers for defence. Its nocturnal habits, propensities for hiding in the dark places during the day, its ability to compress its body into a very small space, and the peculiar hair on its*body, are the most important of its defensive characteristics.

The hair on a bat is not the round, shaft-like ordinary hair, but consists of lances with pockets on them. If the hair were round it would not afford protection against the long beak of the mosquitoes, but the pockets of the hair catch the end of the mosquito’s beak and prevent it from going in far enough to reach the skin. The bat is, therefore, immune to the attacks of the insect. Nature always gives a creature protection from its enemies. Therefore, if' the hat is the enemy of the mosquito that insect must have a method of protecting itself against the bat. Dr. Campbell experimented to determine just what method the mosquito employed to protect itself. He procured tens of thousands of mosquito eggs and put them in a tub containing cistern water, and placed organic matter in the small room which he used for the test.

Thousands of mosquitoes hatched out. At raght their buzzing noise could be plainly heard outside the small room. The doctor entered the room with a darkened flash light and liberated two bats. Instantly the buzzing ceased and the light showed the mosquitoes .clinging to the wall, perfectly motionless. In less than three minutes after the bats were removed from the room the buzzing was resumed. This test was repeated several times, and the result was always the same. Dr. Campbell concluded from this that the bat is attracted to the mosquito by an abnormally acute hearing, and its sense of smell does the rest. Another convincing proof of the bat’s acute hearing is that its flight is noiseless. The sudden dips and dashes it makes through the air, turning suddenly to points entirely out of its range of vision, could only he induced by hearing some insect in that locality.

By careful examiugtion of the guano deposits of the bats, Dr. Campbell estimated that each bat consumed every day no less than 5000 mosquitoes. If there are 500,000 bats in a roost, they would destroy in one night at least 250,000,000 mosquitoes. It can readily be seen how difficult it would be for these insects to thrive while these bats were in the neighbourhood. A bat roost must be built in harmony with the habits of the bat, or it will prove a failure. Dr. Campbell built one, and spread bat guano about, this giving it the odour familiar to the bat. ’ The bat -has a wonderful sense of smell, which it employs to find its home in distant caves. When the familiar scent was wafted from the artificial roost, it led the hats to investigate and finding the structure a suitable home, with the typical bat odour, they were convinced it was a safe place to lodge. They preferred the new roost to their old habitation in the caves, because it

was close to their feeding grounds and saved them the trouble of long journeys.—” Popular Science Siftings.”