The defendant further offered evidence to prove that a usage and custom existed in the city of Washington, which authorized a tenant to remove any building which he might erect upon rented premises, provided he did it before the expiration of the term. The plaintiffs' objected to this evidence; but the court admitted it. This constitutes the second exception.

Testimony was then introduced on this point, and after the examination of the witnesses by the defendant, the plaintiffs prayed the court to instruct the jury that the evidence was not competent to establish the fact that a general usage had existed or did exist in the city of Washington which authorized a tenant to remove such a house as that erected by the tenant in this case; nor was it competent for the jury to infer from the said evidence that such a usage had existed. The court refused to give this instruction, and this constitutes the third exception.

The counsel for the plaintiffs then introduced witnesses to disprove the usage; and after their testimony was given, he prayed the court to instruct the jury that, upon the evidence given as aforesaid in this case, it is not competent for them to find a usage or custom of the place by which the defendant could be justified in removing the house in question; and there being no such usage, the plaintiffs are entitled to a verdict for the value of the house which the defendant pulled down and destroyed. The court was divided and did not give the instruction so prayed; and this constitutes the fourth exception.

The first exception raises the important question, what fixtures erected by a tenant during his term are removable by him?

The general rule of the common law certainly is that whatever is once annexed to the freehold becomes part of it, and cannot afterward be removed, except by him who is entitled to the inheritance. The rule, however, never was, at least as far back as we can trace it in the books, inflexible and without exceptions. It was construed most strictly between executor and heir in favor of the latter; more liberally between tenant for life or in tail, and remainderman or reversioner, in favor of the former; and with much greater latitude between landlord and tenant in favor of the tenant. But an exception of a much broader cast, and whose origin may be traced almost as high as the rule itself, is of fixtures erected for the purposes of trade. Upon principles of public policy, and to encourage trade and manufactures, fixtures which were erected to carry on such business were allowed to be removed by the tenant during his term, and were deemed personalty for many other purposes. The principal cases are collected and reviewed by Lord Ellenborough in delivering the opinion of the court in Elwes v. Mawe, 3 East's R. 38; and it seems unnecessary to do more than to refer to that case for a full summary of the general doctrine and its admitted exceptions in England. The court there decided, that in the case of landlord and tenant there had been no relaxation of the general rule in cases of erections solely for agricultural purposes, however beneficial or important they might be as improvements of the estate. Being once annexed to the freehold by the tenant they became a part of the realty and could never afterward be severed by the tenant. The distinction is certainly a nice one between fixtures for the purposes of trade and fixtures for agricultural purposes; at least in those cases where the sale of the produce constitutes the principal object of the tenant, and the erections are for the purpose of such a beneficial enjoyment of the estate. But that point is not now before us; and it is unnecessary to consider what the true doctrine is or ought to be on this subject. However well settled it may now be in England, it cannot escape remark that learned judges at different periods in that country have entertained different opinions upon it, down to the very date of the decision in Elwes v. Jlfawe, 3 East's R. 38.

The common law of England is not to be taken in all respects to be that of America. Our ancestors brought with them its general principles, and claimed it as their birthright; but they brought with them and adopted only that portion which was applicable to their situation. There could be little or no reason for doubting that the general doctrine as to things annexed to the freehold, so far as it respects heirs and executors, was adopted by them. The question could arise only between different claimants under the same ancestor, and no general policy could be subserved by withdrawing from the heir those things which his ancestor had chosen to leave annexed to the inheritance. But between landlord and tenant it is not so clear that the rigid rule of the common law, at least as it is expounded in 3 East, 38, was so applicable to their situation as to give rise to necessary presumption in its favor. The country was a wilderness, and the universal policy was to procure its cultivation and improvement. The owner of the soil as well as the public had every motive to encourage the tenant to devote himself to agriculture, and to favor any erections which should aid this result; yet, in the comparative poverty of the country, what tenant could afford to erect fixtures of much expense or value if he was to lose his whole interest therein by the very act of erection? His cabin or log hut, however necessary for any improvement of the soil, would cease to be his the moment it was finished. It might, therefore, deserve consideration whether, in case the doctrine were not previously adopted in a State by some authoritative practice or adjudication, it ought to be assumed by this court as a part of the jurisprudence of such State upon the mere footing of its existence in the common law. At present it is unnecessary to say more than that we give no opinion on this question. The case which has been argued at the bar may well be disposed of without any discussion of it.