1 88 HARVARD LAW REVIEW. statute could be more strictly construed than the rule of exemp- tion as applied in that case. A ship which the tenant was building for the plaintiff was distrained by the defendant. The title had passed, according to the peculiar rule of the English law in regard to ships, while the building was going on. The ship was thus the plaintiffs property; it was being worked on by the tenant, whose trade consisted in working upon other men's goods ; and if the plaintiff had only delivered it to the tenant, the exact terms of the rule acted on in Muspratt v. Gregory would have been satisfied. It was urged that this lack of a delivery was im- material. But the Lord Chancellor replied that he was not at liberty to inquire whether one part of the rule was more essential than another; he was limited to its precise terms. He therefore held, though expressing regret at the result, that the absence of a delivery was fatal to the plaintiff's claim of exemption. Lord Esher, in concurring, said the exceptions laid down in Sampson v. Hartopp were " stated in the form of rules, not principles, and that distinction was upheld in Muspratt v. Gregory, where the court was asked to find that they were principles, but refused to do so." In the process of "judicial codification" 1 which these cases have been used to illustrate, the order of development is seen to be, first, the cases ; then the rule, growing up by successive decis- ions and taking on a definite shape ; then the application of that rule, like a statute, to further cases. This development, however, is very gradual. The process of working out analogies by a princi- ple (to adopt Lord Esher's distinction between " principles " and " rules "), and that of applying the final judge-made rule, shade into one another by imperceptible degrees, and it may be impos- sible to say at any given time whether a decision is new law, or is merely the application of an existing rule. Different branches of the law reach the final stage at very different periods, according to the lines in which society develops. As the pursuits and inter- ests of men turn in one direction, the cases on that subject become numerous, the analogies multiply, and the law passes into a com- paratively rigid condition. This happened at an early time to the English law of real property in some branches, and its growth has therefore required the aid of the legislature to an unusual degree. On other subjects we are at the present time passing 1 Maine, Village Communities, 368.
