If railroads had no obligations or advantages beyond those of other common carriers, such as stage lines and steamship companies, their discriminations might be less objectionable, but, as keepers of the toll-gates of the public highways, they are no more at liberty to regulate their own business regardless of the public welfare than were their predecessors, the toll-collectors stationed along the public turnpikes and canals. As such public tax-collectors they are bound to give equal treatment to all persons and places. Although the business of constructing and keeping in repair the turnpike roads was, as a rule, left to private persons, and the promoters of such enterprises were permitted to reimburse themselves for their outlay by the collection of tolls, their schedules of tolls were prescribed by the State and their business was placed under the supervision of public officers, whose duty it was to see that neither extortion nor discrimination was practiced in the collection of these tolls, and that the private management of a public business did not become the source of abuse. The State thus insisted upon exercising a restraining influence over the business of turnpike companies because it realized the danger of entrusting the management of a semi-public business to companies organized solely for private gain, with officers responsible only to their stockholders, who, under ordinary circumstances, could be relied upon to measure the usefulness of an employe by his ability to contribute to the increase of the annual dividends. It will scarcely be claimed, even by railroad men, that since the days of turnpikes and stage-coaches corporations have become more unselfish and their officers less servile. The temptations have increased, while human frailty remains the same.