How Lord Holt came to distinguish between bailees for reward and others has been shown above. It is more pertinent here to notice that his further qualification, exercising a public calling, was part of a protective system which has passed away. One adversely inclined might say that it was one of many signs that the law was administered in the interest of the upper classes. It has been shown above that if a man was a common farrier he could be charged for negligence without an assumpsit. The same judge who threw out that intimation established in another case that he could be sued if he refused to shoe a horse on reasonable request. /2/ Common carriers and common innkeepers were liable in like case, and Lord Holt stated the principle: "If a man takes upon him a public employment, he is bound to serve the public as far as the employment extends, and for refusal an action lies." /3/ An attempt to apply this doctrine generally at the present day would be thought monstrous. But it formed part of a consistent scheme for holding those who followed useful callings up to the mark. Another part was the liability of persons exercising a public employment for loss or damage, enhanced in cases of bailment by what remained of the rule in Southcote's Case. The scheme has given way to more liberal notions; but the disjecta membra still move. Lord Mansfield stated his views of public policy in terms [204] not unlike those used by Chief Justice Holt in Coggs v. Bernard, but distinctly confines their application to common carriers. "But there is a further degree of responsibility by the custom of the realm, that is, by the common law; a carrier is in the nature of an insurer.... To prevent litigation, collusion, and the necessity of going into circumstances impossible to be unravelled, the law presumes against the carrier, unless," &c. /1/