
84 U.S. 460 (1873)
17 Wall. 460
PHILP ET AL.
v.
NOCK.
Supreme Court of United States.

*461 Mr. R.D. Mussey, for the plaintiff in error.
Mr. G.W. Paschall, contra.
*462 Mr. Justice SWAYNE delivered the opinion of the court.
The measure of the damages to be recovered against infringers prescribed by the act of 1836 as well as by the act of 1870, is "the actual damages sustained by the plaintiff." Where the plaintiff has sought his profit in the form of a royalty paid by his licensees, and there are no peculiar circumstances in the case, the amount to be recovered will be regulated by that standard. If that test cannot be applied, he will be entitled to an amount which will compensate him for the injury to which he has been subjected by the piracy. In arriving at their conclusion, the profit made by the defendant and that lost by the plaintiff are among the elements which the jury may consider. Where the infringement is confined to a part of the thing sold, the recovery must be limited accordingly. It cannot be as if the entire thing were covered by the patent; or, where that is the case, as if the infringement were as large as the monopoly. Counsel fees cannot be included in the verdict. The plaintiff must show his damages by evidence. They must not be left to conjecture by the jury. They must be proved, and not guessed at.
The instruction under consideration was too broad and too vague. The jury could have hardly doubted that it was their duty to allow the counsel fees paid or to be paid by *463 the plaintiff, and perhaps other charges and expenditures equally inadmissible.
JUDGMENT REVERSED, and the cause remanded to the court below, with directions to issue
A VENIRE DE NOVO.
