It is a commonplace in the law that no court has defined, or ever will consent to define, the exact limits of this police power; suffice it to say that in the classic words of Chief Justice Shaw of Massachusetts, "it is all that makes for the health, safety, or comfort of the people." As to the health and safety, there can be little question; but when it comes to indefinite words like "comfort" or "well-being," too wide a field is left for the imagination. It has recently been decided that the aesthetic part of life does not necessarily concern the comfort or well-being of the people. That is to say, laws forbidding the use of land for the erection of hideous signs, or forbidding the height of buildings at an inartistic excess have been declared not to fall within the police power, but under eminent domain. So of statutes forbidding the taking of a man's picture, or a woman's portrait for advertising purposes, when not properly obtained; yet it may be questioned if any law is more certainly for the comfort of the persons concerned than such a statute. On the other hand, noisy or noxious trades, mosquito ponds, trees infected with moths, etc., sawdust in water, offensive smoke, and, in Vermont, signs, were all made nuisances by statute of one State or other in 1905 alone. The first historical instance, perhaps, of destruction of property under the police power was the blowing up of buildings to check a conflagration, a practice still common, although its utility was much questioned after the Boston fire, and which, at common law at least, gave the owner no right to compensation; but the more usual use of the police power until very recent years has been limited to the prohibition of offensive trades in certain localities, and the suppression of public nuisances. Later, the prohibition of the manufacture of intoxicating or malt liquors, and the regulation of tenement houses at the orders of the Board of Health. This led to the regulation or prohibition of certain trades conducted in tenement houses or in sweat shops, and to other matters which we shall find it more convenient to consider under the head of labor legislation.