In this country perhaps more than in any other a fashion, a song, a word, an expression, a mechanical gadget or an idea, when it happens to strike the popular fancy, sweeps over the country like a prairie fire. Many of these pass and disappear as rapidly as they came, but others, when they are bolstered by an outstanding personality or by systematic and persistent advertising, may continue indefinitely and may become, so to speak, a part of our folklore. Some of these things, especially gadgets and ideas which are associated with the use of gadgets, are immediately taken up by commercial exploiters who proceed to "cash in"; and as the cash rolls in, or even before, a corporation is organized, partly to hide the identity of the exploiters and partly to increase the take by all the means known to high pressure exploiters. One of the principal methods is