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Page:Popular Science Monthly Volume 90.djvu/398

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��Popular Science Monthly


��The Automatic Traffic Controller. No Law- Breaking Speeder Can Escape It

ENERGETIC drivers who use the city streets for a race course would find their riding rather rough if the streets were fitted with John J. Keenan's traffic controller. It is guaranteed to stop in re- cord time any driver who is trying to defy the speed laws.

The device, as the illustration shows, embodies a series of short .steel arms which are fitted across a narrow trough in the ground. The arms, strung one after an- other across the corner of a street, con- nect at [^the bottom ^witli a long bar. This bar can be worked back and forth within the trough by means of its gearing connection with a turnable upright post. Through this bar, the arms can be made to turn around until they project above the street when the post is swung around in one direction. When the post is swung in the opposite direction, on the other hand, the arms are turned downwardly until they are flush with the level of the street, thereby closing up the trough.

An elaborate electric signaling system connects each post with all the others that may be placed at the important points along the main highways. Should a party

��At left is a diagram that explains the operative principle of the device. In the picture above the fxsliceman at the central post in the middle of the street has thrown the apparatus into operation

��of autoists come tearing down the street, the policeman who first sees them signals •ahead to other officers. They in turn throw the apparatus in operation. ' Unless the autoists heed the warning to stop, they will find that the projecting arms will have punctured a tire or two, or will have ripped off some of their mechanism. If the police- man should have deemed it necessary to telephone all the stations in the city to be thrown in, there would be little chance for anybody to get away.

��Grafting with Frog's Skin Gives Satisfactory Results

THE idea of grafting with frog's skin was put into practice as early as 1886. Recently fourteen cases of successful graft- ing were reported in France. The ideal wound to graft is flat, and without excessive granulations.

The method of applying the frog's skin is as follows. The wound is first gently cleaned without antiseptics and as gently dried. Then the loose skin on the inner side of the frog's thigh is carefully pinched up in a pair of dressing forceps, snipped off with scissors, spread out and applied by its under surface to the wound. A strip of gutta-percha tissue is then placed over it and fixed in position at its ends by adhesive plaster. Then a dry dressing is applied over all. The wound heals with remarkable rapidity after the grafting. Frog's skin is used, however, only in places where it will not be conspicuous.

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