382 



Popular Science Monthly 



PERATING HANDLE GUARD IN INOPERATIVE 

 GUARDS IN OPER- POS'TIOM 0^ STREET 

 ATlve POSITION LEVEL 



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. 



