§ 418. AN action of trespass on the case, is prescribed by the United States statutes, as the proper legal remedy, for infringements of patents.' Patent rights are not based upon the common law; but are founded wholly upon the Constitution and statutes of the United States. Where a statute creates a right, and prescribes a legal remedy for

1 Revised Statutes, Section 4919.

2 Section 149 of this book.

its enforcement, it is the general rule that no other common law remedy can be used for that purpose.' Unless patent rights are exempt from this rule, it will follow that an action of trespass on the case is the only action which United States courts can entertain, when sitting as common law courts in patent cases. Whether patent rights are thus exempt, is a question which once arose in a Supreme Court case, but which was not decided because it was apparently overlooked by the counsel and by the court.

The case was that of the Packet Co. v. Sickles. It was originally an action of assumpsit, based on an alleged contract between the parties, relevant to compensation for the use of a patented machine. A recovery was adjudged on that contract in the court below; but the Supreme Court reversed the judgment on the ground that the contract was not in writing, and was not to be performed within one year, and was therefore void under the statutes of frauds. On the case being remanded, the plaintiff amended the declaration by adding two counts in assumpsit for money had and received. The case was thus changed from an action of assumpsit on a contract, to an action of assumpsit to recover compensation for the infringement of a patent. The defendant did not notice the questionable propriety of an action of assumpsit for that purpose, and therefore pleaded non-assumpsit. The jury found for the plaintiff, and having been instructed by the court to assess the damages on the basis of the value of the use of the machine, it rendered a verdict for $11,333, with interest from the day when the suit was brought.

Now if an action of assumpsit had been proper, it would be difficult to show any impropriety in the charge of the court, though in an action of trespass on the case it would have been clearly wrong.' When the case again reached

1 Wiley &. Yale, 1 Metcalf (Mass.), 554, 1840; Elder v. Bemis, 2 Metcalf (Mass.), 604, 1841; Smith v. Woodman, 8 Foster (28 N. H.), 528, 1854.

2 Packet Co. v. Sickles, 5 Wallace, 580, 1866.

3 Seymour v. McCormick, 16 Howard, 480, 1853.

the Supreme Court, it was again reversed; this time because the charge did not conform to the precedents relevant to the measure of damages in actions at law for infringements of patents. But no due notice appears to have been taken of the fact that the case at bar was an action of assumpsit, while those precedents had been established in actions of trespass on the case.' Had that distinction been attended to, the court could hardly have sustained the propriety of the form of action, and at the same time have reversed the case for error in the charge. The suit was treated precisely as though it had been an action of trespass on the case. If the court had meant to affirm the propriety of actions of assumpsit for infringements of patents, it would not have so treated the suit; for its ruling would seem to be inappropriate to that form of action. The precedent is therefore not fairly citable on either side of the question of the propriety of an action of assumpsit for the infringement of a patent.

§ 419. That an action of assumpsit may be based on an infringement of a patent, has been stated to be the law by at least two United States judges.'

In the first case cited, Judge HUGHES said: "Let us now suppose the case of a person who takes possession of and uses another's horse, wagon and team, or threshing-machine, without his knowledge, consent, or authority. . . . In such a case, the owner may recover damages in trespass for the tort; or he may waive the tort, and sue in assumpsit on the implied promise to pay what is equitably due for the use and possession of the property. . . . The case I have supposed is, in principle, precisely the case we have at bar, for there is no magical quality in the property of a patentee in his patent to distinguish this case from the one just supposed, where ordinary property had been taken and used without the owner's consent. . . The act of the defend

Packet Co. v. Sickles, 19 Wallace, 617, 1873.

Sayles v. Richmond, Fredericksburg & Potomac Railroad Company,

...

4 Bann. & Ard. 245, 1879; Steam Stone Cutter Co. v. Sheldons, 15 Fed. Rep. 609, 1883.

ant was nothing but the simple one of a person taking and using another's property, without authority, to his own advantage, and incurring a liability to compensate the owner for such use of the property. The case is, in principle, precisely identical with that of such a use of a horse, or a boat, or a wagon and team, or threshing-machine-giving a right of action in assumpsit.'

In the second case Judge WHEELER said: "When the Windsor Manufacturing Company sold machines, embodying these inventions, to the defendants for use, it invaded the orator's rights and converted the orator's property to its own use. These acts were tortious, and an action would lie for these wrongs. As that company received money for the orator's property, the orator could waive the tort, and sue in assumpsit for the money, or, what is the same in effect, proceed for an account of the money received. In an action or proceeding for the money, the measure of damages would be the amount of money received, not the amount of damage done, and all right of recovery beyond that would be waived."

§ 420. It is against the policy of the law that the owner of a patent right should lose by reason of its infringement. To prevent such a result, the action of trespass on the case is well adapted, because it measures the plaintiff's recovery by the plaintiff's loss. But it is also against the policy of the law that an infringer should gain by reason of his infringement. To prevent such a result, the action of trespass on the case is not well adapted, because an infringer may often gain far more than the patentee loses by reason of the wrongful act of the former. Patents are peculiar property in this respect. A horse or a wagon is worth about as much to one man as to another, but the use of a patent may be worth ten times as much to a rich infringer as to a poor patentee. It would be a reproach to the patent laws if any infringer could unlawfully make, use, and sell specimens of his neighbor's patented invention, and, when called to account in a court of justice, could cancel his liability by paying one tenth of the proceeds of his tort to