The statute provides that damages for an infringement may be recovered in an action on the case in any circuit court of the United States, or district court exercising the jurisdiction of a circuit court, or in the Supreme Court of the District of Columbia, in the name of the party interested, either as patentee, assignee, or grantee. (h)

The statute also provides, in a section which we give in a note, for certain defences which may be proved in trial under the uu general issue. (t) If any of these defences are made, * thirty days' notice must be given. But other defences may be made without this notice. As, that there is no infringement; or,

(h) Act 1870, § 59.

(i) Act 1870, § 61. "In any action for infringement, the defendant may plead the general issue; and having given notice in writing to the plaintiff or his attorney, thirty days before, may prove on trial any one or more of the following special matters: 1st. That, for the purpose of deceiving the public, the description and specification filed by the patentee in the Patent-Office was made to contain less than the whole truth relative to his invention or discovery, or more than is necessary to produce the desired effect; or, 2d. That he had surreptitiously or unjustly obtained the patent for that which was in fact invented by another, who was using reasonable diligence in adapting and perfecting the same; or, 3d. That it had been patented or described in some printed publication prior to his supposed invention or discovery thereof; or, 4th. That he was not the original and first inventor or discoverer of any material and substantial part of the thing patented; or, 5th. That it had been in public use or on sale in this country for more then two years before his application for a patent, or had been abandoned to the public. And in notices as to proof of previous invention, knowledge, or use of the thing patented, the defendant shall state the names of patentees and the dates of their patents, and when granted, and the names and residences of the persons alleged to have invented or to have had the prior knowledge of the thing patented, and where and by whom it had been used; and if any one or more of the special matters alleged shall be found for the defendant, judgment shall be rendered for him with costs. And the like defences may be pleaded in any suit in equity for relief against an alleged infringement; and proofs of the same may be given upon like notice in the answer of the defendant, and with like effect" The defences specified in this section may also be pleaded specially. Grant v. Raymond, 6 Pet. 246; Evans v. Eaton, 3 Wheat. 503. Where reference is made to a prior printed publication, it should be to the part of the work intended to be relied on. A mere reference to the title is not sufficient. Silsby v. Foote, 14 How. 22, affirming s. c. 1 Blatchf. 454. And it has been held, that a book of plates without letterpress is not a "printed publication" admissible in evidence under this section. Judson v. Cope, 1 Fish. 616. The notice need specify only the names of the persons having the prior knowledge, but not the names of the witnesses by whom such knowledge is to be proved. Many v. Jag-ger, 1 Blatchf. 376; Wilton v. Railroads, 1 Wall. Jr. 195. Otherwise held in the seventh circuit, Judson v. Cope, 1 Fish. 615.

♦257 vv that the patent is invalid, because the patentee is a person to whom the patent cannot be granted; or because the invention is wanting in the qualities made requisite by statute; or because the patent is deficient or erroneous in some of the formalities essential to its validity. (j)