SMASH THAT FLY.

Kaipara and Waitemata Echo, 28 August 1914, Page 2

SMASH THAT FLY.

The common house-fly, the Musca dornestira of Linnaeus, that insect which figures in fable and poetry, and is popularly regarded as a harmless, innocent, lively and intereating creature, which may lie looked upon with indifference, or at most struck at with objurgation when too familiar, proves to heone of our worst enemies. Its relations to human life and .sanitation are most important, and yet for years all efforts to bring the facts :>i its noxious existence properly to the attention of people met with indifference or ridicule. In a striking paper Mr. N. A. Cobb instructively discusses, with pictorial accompaniments, the menace of the house-fly. "The fly's power to spread disease," says Mr. Cobb, "is a direct function of its powers of locomotion. It can fly considerable distances at a high rate of speed. It is quickly carried long- distances by trains, boats animals and man. "It is possible to get a good idea of a fly's rate of flight in a number of ways. Flies,come to ships newly arrived in port across considerable stretches of water. This we know, because a few hours earlier there were no flies on the ship. No communication has been had with land. The flies must have come on; their own wings. Occasionally we > see a fly follow a team or animal, easily keeping up a good pace. The wing muscles of a <fly when weighed are found heavier in proportion than those of any bird so far examined. It is difficult to tire a fly out. Test this by trying to keep one constantly on the wing in a room and you will soon find you have no easy taskt. All this shows the fly to be no mean -navigator of the air. "Most of'our diseases are caused by invisible germs. These germs may be brought to us from sick persons by whatever is large enough to carry them and has the opportunity. Combine this fact with what every one knows about flies, and we see at once the tremendous importance of flies as carriers of human disease germs. "The result of this simple piece of reasoning is so startling that it is often sidetracked by its own importance. It looks so incredible that we hesitate, distrusting our own .logic. It seems incredible that men have gone on doing as they have done, and as they are still doing, if the facts are 'as they seem. The consequences of our reasoning seem so tremendous, we fear there must have been a mistake somewhere. And so we dismiss the idea. One way to disturb this false security is to interest people in the habits and structure of flies. The more we know about flies, the more clear it will become that they are among our worst enemies. "Take the view of the fly resting on glass and viewed from below. Look at the feet, and observe that each of them has two claws and the two light-coloured pads. The fly clings to rough surfaces by a combined action of the claws and pads. The ' fly's pads are covered with thousands of minute short hairs, sticky at the end. There is no suction —merely adhesion. "T.he action of a fly's pads may be illustrated by means of a piece of sticking plaster and a few threads and small weights. Take a piece of sticking plaster half an inch wide iind sew through it some short pieces of thread at intervals of half aii inch, and knot the threads on the sticky side so that they cannot pull through. Stick the plaster to a dinner plate .or other smooth object, and if will be found that if a small weight is attached to each thread the plaster will sustain in this way a considerable weight—that is to say, the sum of all the small weights Js considerable. HOW GERMS ARE CARRIED BY THE FLY. . -Now, removo the weights and attach all of them to one or two of the threads at one end. The plaster will promptly be torn loose. Acting on a portion of the plaster nt a time, the weights can accom T aJish what they cannot accomplish .vhen distributed along the whole surface of the plaster. This experiment illustrates roughly how the fly uses and . controls its feet. Wonderful as the fly's pads are, they have their' disadvantages, for stickiness and locomotion are not alwa\s .strictly compatible. All his grownup life the fly has to manage with sticky feet. Imagine our plight if the soles of our feet * were sticking plaster, perennially renewing its stickiness ! Whoever has experienced the sticky mud of certain legions will recall how the boots ball up and what a conglomera-: tion one drags home from a ramble under such circumstances. "To such inconveniences the fly is constantly subject, and it is this that has bred in him a ha hit of frequently preening himself, particularly his feet. Tlie.se an; cttustMctly becoming clogged with adhering substances, and this contamination the fly must assiduously remove if his feet are to act properly in supporting him on slippery places. If this contamination is tot; sticky to rub off the fly laps it off. and it then passes off in his excreta. " Thus it is that all sorts of microscopic particles are n. -. ;>d from place to place on the feet of flies. These particles are rarely of sufficient size to be seen with , r.he unaided eye. Nevertheless, they are constantly present, and the amount of matter thus transferred is relatively considerable on account of

oily's activity. When flies have ac<css to diseased or rotten or foul matter, the transfers thus effected are dangerous. All sorts ofi minute organisms arc spread in this way, including diseases of man, ianimals, and plants. It is impossible! to go into details in this place, buit it is only right to say that the imagination completely fails to> grasp the far-reaching consequences of this transfer of germs and spores on the feet of flies."—" Popular Science

Siftings."