THE MISSION' OF THE HOUSE FLY.

Dunstan Times, Issue 703, 8 October 1875, Page 4

THE MISSION' OF THE HOUSE FLY.

—o— The fly when it alights rubs its 'hind legs together; then each hind leg is passed over a wing ; then the same operation is performed with the fore legs; and then, if you observe closely, you will see Mr Fly pass his trunk or proboscis over his legs and about his body as far as he can reach. The trunk terminates in two large lobes, which spread out when the insect begins a meal and is capable of being drawn back rapidly ; but though thus constituted it is not fitted for licking, but simply for grasping and drawing up food. What the fly does by flying around and then alighting and going through the manoeuvres described has at length been successfully investigated and decided by an English chemist named Emerson, who carried out his work by the aid of a powerful microscope. He relates that when he first conceived the idea of making the investigation ho captured a fine specimen and glued its wings down to a microscope slide. On placing the slide under the instrument he found to his disgust that the fly appeared to be COVERED WITH VERMIN. He tried several others, which were likewise covered with lice, and this curious coincidence led him to still further investigation. Why were the flies thus afflicted, or wa» it an affliction 1 Watching one of the flies fastened on the slide more closely he observed the creature extend its proboscis and sweep it over bis body, as if he had just alighted. Whei-ever the lice were the trunk went; they were disappearing within its recesses ; the fly was actually eating them. At first he thought this vet min the fl y’s progeny, but further investigation disproved this. Mr Emerson took a piece of wh'te paper, on which two flies had lighted and were licking themselves, and putting it under the instrument found some of the little creatures had fallen off—crumbs from the table, so to speak. He then tock the-paper, went into the kitchen and waving it around his head, taking care that no fire touched it during the operation, went back to the microscope and there found animalcules floating in the air. The body of the fly is covered with a coarse long hair, and its quick motions serve to take them up, as the hairy mouth of the whale takes up the anima’cules of the sea. When he gets •the net full the fly retires to his favorite rec°ss on the window sill or in a quiet corner, and proceeds to devour his FEAST OP SOFT SHELL CRABS. Mr Emerson continued his investigations in a variety of places, and the more dirtv and filthy the place, the more foetid the odor pervading it, the richer the harvest he found the flies had made in the animalcule line. While the flies captured in such filthy places were usually fat, and pie thoric, and happy, the flies found in clear and well-ventilated apartments were so lean and miserable that when a spider caught one of them in his “ parlor ” he immediately kicked it out as not fit to eat. Wherever filth existed, evolving germs that might generate disease, there Mr Emerson observed that the flies were most attracted,. and there they covered themselves with the minute organisms which they greedily devoured. From this can lie deduced the conclusion that while the mission of house flies is one of immense importance to man, their presence in immerse numbers, while it indicates unhealthy exhalations, also guarantees immunity from disease to some extent. Of course the house fly, which has a penchant for bald heads, and lights on the skin only to puncture it and draw blood is not here taken into account. Such flies should not receive any credit, even if they deserved it.—Exchange.