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Show Keeping Down Fever by Keeping Ducks MVLARIA and yellow fever are both spread by moSqultoes. The only problem before humanity In getting rid of the two fevers is to get rid of the insects that carry the fever germs. Dr. Samuel G. Dixon, State Health Commissioner of Pennsylvania, writing for the Journal of the American Medical Association, advocates keeping ducks to keep down the two diseases. It used to be thought, and it is still a common delusion, that malaria especially especial-ly was "caught" by inhaling bad air. It has been proven beyond doubt that the only wav the germ either of it. or yellow fever can be communicated is through the bite of the mosquito. When the mosfjuito takes up the fever germs in marshes and low-lying places, the germ it h r: I f has no effect, upon the insect, but when it inserts its cutting and sucking apparatus into man, the bacilli makfi thir v.;;v into the human blood in practically prac-tically tbo 8i mo way as though injected by a hyjindermic needle. Dr. Dixon points out that "the duck has I' he "Aide.-' l geographical range of any bird. It. Is an omnivorous eater of the 'mosquito's ymwr. Besides its appetite iis movei.'i'-nt trough the water crealps w'atfr jnnrinng which drown the mosquito :ouiig which. Just before they hatch into tii" mil fledc-d p"-ts. turn from wrig-slT,. wrig-slT,. into pupa", v hieh are air breathers. Tin-Hr pMpac float upon the surface of tin! v. atcr diiring the brief period of ni"!!!niorfiioMS into the winged inject. Thfy nfij to breathe. Any medium v.liiih mibm'-rgca tliem, drowns them. 1 ie.-tri bing his experiments on ducks a,. ni'iMiuito destroyers. Dr. Dixon savn: "AftT trying the ability of fish to devour de-vour larvae anil pupae of mosquitoes, i!i!ii varied success, I huilt two (lama near together on the same stream, so ilia I. tacli would have the same environment environ-ment for the breeding of mosquitoes. Each covered nearly 1,400 square feet. In one, twenty mallard ducks were permitted per-mitted to feed, while the other was entirely en-tirely protected from water fowl, but well stocked with gold fish. "The pool in which the ducks fed was for several months entirely free from mosquitoes, while the pond protected from ducks and slocked with fish was swarming with young Insects in different cycles of life. "In the infested pond the one that had been stocked with gold fish ten well-fed mallard ducks were then admitted, and as they entered the pond they were first attracted by the tadpoles. They, bow-ever, bow-ever, soon recognized the presence of the young of the mosquito, both in the wriggler wrig-gler and larvae stage, and Immedlataely turned their attention fo (hese, ravenously raven-ously devouring them In preference to any other foodstuff present. At the end if twenty-four hours no pupae survived. The motion of the water, made by tin: ducks, of course drowned some of the Insects- what proportion cannot be estimated. es-timated. "For some years I have been using ducks to keep down inosquiloes in swamps that, would have been very expensive ex-pensive to drain, hut. I never fully appreciated ap-preciated the high degree of efficiency or (he duck as n deii rover of mosquito life until the foregoing test, was made. "Mr. William Dock wood, of Host on,- an artist who made a hobby of raising aquatic, fowl, also exprciseH an opinion that the spoon-hilled duck Is particularly adapted to the destruction of mosquito larvae roMing on the surface. "Ducks can be used In ponds, sv. amps, both open and In Jungles, and can lie driven from place to place. Sol only can they be ge-oi-ally used lo keep down mosquito life, but ihey also furnish a delicious and valuable foodstuff." |