A common carrier is liable for goods which are stolen from him, or otherwise lost from his charge except by the act of God or the public enemy. Two notions have been entertained with regard to the source of this rule: one, that it was borrowed from the Roman law; /2/ the other, that it was introduced by custom, as an exception to the general law of bailment, in the reigns of Elizabeth and James I. /3/ I shall try to show that both these notions are wrong, that this strict responsibility is a fragmentary survival from the general law of bailment which I have just explained; [181] the modifications which the old law has undergone were due in part to a confusion of ideas which came the displacement of detinue by the action on the case, in part to conceptions of public policy which were read into the precedents by Lord Holt, and in part to still later conceptions of policy which have been read into the reasonings of Lord Holt by later judges. Southcote's Case was decided in the forty-third year of Queen Elizabeth (A.D. 1601). I think the first mention of a carrier, pertinent to the question, occurs in Woodlife's Case, /1/ decided four or five years earlier (38 or 39 Eliz., A.D. 1596 or 1597). It was an action of account for merchandise delivered to the defendant, it would seem as a factor ("pur merchandizer")--clearly not as a carrier. Plea, robbery at sea with defendant's own goods. Gawdy, one of the judges who decided Southcote's Case, thought the plea bad; but Popham, C. J. said that, though it would not be a good plea for a carrier because he is paid for his carriage, there was a difference in this respect between carriers and other servants and factors. This is repeated in Southcote's Case, and appears to involve a double distinction,--first between paid and unpaid bailees, next between bailees and servants. If the defendant was a servant not having control over the goods, he might not fall within the law of bailment, and factors are treated on the footing of servants in the early law. The other diversity marked the entrance of the doctrine of consideration into the law of bailment. Consideration originally meant quid pro quo, as will be explained hereafter. It was thus dealt with in Doctor and Student /2/ when the principle was still young. Chief Justice [183] Popham probably borrowed his distinction between paid and unpaid bailees from that work, where common carriers are mentioned as an example of the former class. A little earlier, reward made no difference. /1/ But in Woodlife's Case, in reply to what the Chief Justice had said, Gawdy cited the case of the Marshal of the King's Bench, /2/ stated above, whereupon Popham fell back on the old distinction that the jailer had a remedy over against the rebels, but that there was no remedy over in the case at bar.