Pre-eminent among the forms of business corruption are the vicious practices which have grown up in the general relation of buyer and seller. Purveyors of adulterated, infected, or diseased consumption goods, such as food stuffs, and particularly meat and milk; dealers in sweatshop clothing; vendors of patent medicines; owners and builders of unsanitary tenement houses, of unsafe theatres, and excursion steamers; managers of railroad and trolley companies who neglect to install devices to protect their passengers may serve as illustrations. A further branch of this form of corruption, the importance of which would perhaps justify separate classification, occurs in connection with the dealers in vice,—the dive keepers, policy kings, gamblers, and procurers. The relation of master and servant furnishes a second subdivision of the primarily economic forms of corruption. Transportation companies, mine owners, manufacturers, and others who neglect the installation of safety devices to protect labourers; the employers of child labour; the labour leaders who extort blackmail by threatening strikes are cases in point. Still another subdivision of economic corruption centres about the fiduciary business relations such as occur particularly in connection with savings banks, trust companies, corporate directorships in general, and with the work of the promoter. Underlying nearly all these kinds of economic corruption, and emerging in the corruption of public instruction and political corruption as well, is competition,—itself a force or method rather than a form. Some species of corruption belonging logically under one or another of the preceding heads exhibit the effects of competition more plainly than others. Thus many practices common to those periods of forced competition which so frequently precede the formation of trusts have come to be looked upon as essentially corrupt and deserving of legal restraint. Corruption does not disappear when competition is practically eliminated, however. Some of the most difficult problems involved in dealing with it notoriously result from the existence of monopolies which have outstripped if they have not exterminated their rivals.