A STARTLING EXPERIMENT.

New Zealand Herald, Volume LX, Issue 18564, 23 November 1923, Page 14

A STARTLING EXPERIMENT.

A scientist caught three flies. They were not' special flies, but he happened to be a man with a "special purpose. He was a scientist, and wanted to know how much truth there might be' in the ilea that flies carry disease. ; One fly was caught in a living room. One was caught out of doors. The third one was trapped in the household refuse bin. He allowed each of. the three flies to walk over a sheet of specially-prepared sterilised jelly, which was incubated. At the end of the fourth day each germ deposited on the ; jelly. had.. grown into a little mass or colony" of microbes, visible to the naked eye, and could be counted and identified. The indoor fly yielded twenty-five colonies of bacteria and six colonies of fungi. The outdoor fly produced forty-six colonies of i bacteria and seven of fungi, while ' the fly from the refuse bin gave no less than 116 colonies of bacteria and ten of fungi. Among. the bacteria were germs of several intestinal diseases, of tuberculosis, several kinds which caused suppuration of the eyes, ears, nose, and other parts of the body. The microbe which causes milk to go sour was present, and so t were ■ the spores which make bread, jam,- fruit, and leather go mouldy. ' ■, While the fly's mode of life may be perfectly satisfactory from the fly's point of: view, says a writer in an exchange, from ours it is most unfortunate. It lays its eggs in manure, filth, human excreta, decaying meat and vegetables, and things of that substances where the garnis of disease abound. The eggs change into maggots . which bury themselves in the filth, in ten days or so become chrysalids, and' v ultimately hatch as flies. " The ; fly's first journey, is over the filth in which it hatches. It next flies straight into our houses and alights on the milk jug, the sugar, < the bread or the meat; sometimes in the dust bin; sometimes on manure or sometimes on the face of the sleeping baby, y': ( . ; , W; ..:; \. ; ' ; ": : :' : ~j - fhe fly's body is covered with bristly hairs—each '. leg - and / foot: being so clad. These hairs catch up and., deposit; the genus*. -i • , ~*•"" • ' 1 The fly, too, has a strange 'habit. It sucks up food into its crop, holds it there temporarily, and then regurgitates it. Supposing after a meal on manure the regurgitation is -on your bread 1 loaf That is what " fly-spots" . consist' of chiefly. .... .. „_ j The stable-fly is in some ways different from the house-fly. It can pierce the j skin with its mouth .parts,' which -are like a hypodermic needle, and thus can actually introduce disease-into-the blood. The house-fly cannot " bite," but deposits its discharge on the surface. If that j surface happens to be a wound on scratch, no matter how small, or a mucous > surface, the microbes deposited may'gain a foothold and cause disease. It is just_ as well to know the science of these things.