difference between the characters of the two inventions.' When evidence of difference of utility between a plaintiff's invention and a defendant's doings, is introduced on an issue of infringement, it must be considered only in connection with all the other evidence upon that subject." If considered alone, it is likely to mislead, because difference of utility often springs from causes which do not constitute substantial difference of invention.

3

§ 377. To constitute an infringement of a patent, it is not necessary that the infringer should have known of the existence of the patent at the time he infringed it; or, knowing of its existence, it is not necessary that he should have known his doings to constitute an infringement."

2

1 Many v. Sizer, 1 Fisher, 27. 1849. Singer v. Walmsley, 1 Fisher, 585, 1860.

3 Parker v. Haworth, 4 McLean, 373, 1848; Matthews v. Skates, 1 Fisher, 608, 1860; National Car Brake Shoe Co. v. Mfg. Co. 19 Fed.

Rep. 520, 1884; Royer v. Coupe, 29 Fed. Rep. 361, 1886; Bate Refrigerating Co. v. Gillett, 31 Fed. Rep. 815, 1887.

4 Parker v. Hulme, 1 Fisher 54, 1849.

CHAPTER XVII.

COURTS PARTIES AND CAUSES.

403. Agents, salesmen, and employ-
ees as defendants.

404. Employers as defendants.
405. Persons as defendants who have
caused others to infringe.

406. Joint infringers as defendants.
407. What facts constitute joint in-
fringement.

408. Partners as defendants.

409. Private corporations as defendants.

410. Officers, directors, and stockholders of corporations as defendants.

411. The same subject continued.
412. Stockholders of corporations.
413. Officers of corporations.
414. Directors of corporations.
415. Statutory liability of officers,
directors, and stockholders of
corporations.

416. Consolidated corporations as de-
fendants in actions based on in-
fringements committed by their
constituent corporations.

417. Causes of action based on a plurality of patents, or on both terms of an extended patent.

§ 378. THE foregoing part of this text-book treats of the rights of inventors and patentees, and of their assignees, grantees, licensees, and legal representatives; and also treats of the wrongs which are committed when those rights are infringed. The remaining part explains the remedies which may be invoked, sometimes to prevent, and sometimes to repair such wrongs of infringement. The present chapter is devoted to the courts which may originally administer those remedies; and to the parties who may invoke them, and against whom they may be invoked; and to the causes of action which justify patent litigation between those parties in those courts.

$379. The Circuit Courts of the United States have original jurisdiction, regardless of the amount involved, of all suits at law or in equity arising under the patent laws of the United States.' The few District Courts of the United States which have Circuit Court powers, have the same jurisdiction in patent cases that the Circuit Courts have in other districts. The same jurisdiction belongs also to the District Courts of the Territories of the United States;' and to the Supreme Court of the District of Columbia.*

Revised Statutes, Section 629; Miller-Magee Co. v. Carpenter, 34 Fed. Rep. 434, 1888.

Revised Statutes, Section 571, as amended January 31, 1877, 19 Statutes at Large, Ch. 41, p. 230.

3 Revised Statutes, Section 1910, and Section 1911, as amended June 29, 1876, 19 Statutes at Large, Ch. 154, p. 62.

Sections 760 and 764 of the Revised Statutes relating to the District

§ 380. Whether State courts have any jurisdiction of actions for infringements of patents, is a question of great interest, upon which it is not possible, at this writing, to give a positive answer. Under the Revised Statutes, the question was clearly answerable in the negative; but in 1875 Congress enacted a statute which provided: “That the Circuit Courts of the United States shall have original cognizance, concurrent with the courts of the several States, of all suits of a civil nature at common law or in equity, where the matter in dispute exceeds, exclusive of costs, the sum or value of five hundred dollars, and arising under the Constitution or laws of the United States." " The constitutional provision relevant to the subject is that: "The judicial Power of the United States, shall be vested in one Supreme Court, and in such inferior Courts as the Congress may from time to time ordain and establish." In view of this organic law, it is certain that Congress cannot confer any judicial power upon any other than Federal courts.* Therefore the statute of 1875 could not have such an operation, even if it purported to do so, and it does not so purport. What it says about concurrent jurisdiction of the State courts, is by way of recital, rather than by way of grant. It appears to assume, that in the absence of congressional prohibition, the State courts would inherently have concurrent jurisdiction, and it removes the prohibition contained in the Revised Statutes."

The real question therefore is, whether, in the absence of congressional prohibition, State courts have jurisdiction of actions arising under the Constitution and laws of the United States. Upon that question, the great constitutional lawyers who have treated it, differ in opinion.

§ 381. The first in point of time, was that author whose

of Columbia. Cochrane v. Deener, 94 U. S. 782, 1876.

' Revised Statutes, Section 711. 218 Statutes at Large, Part 3, Ch. 137, Section 1, p. 470.

3 Constitution of the United

States, Article 3, Section 1.

4 Martin v. Hunter's Lessee, 1 Wheaton, 330, 1816; Houston v. Moore, 5 Wheaton, 27, 1820.

Revised Statutes, Section 711.

opinions on law points never had the technical force of judicial decisions, but whose intellect was so extensive in its grasp, and so powerful in its operation, that whatever he wrote in the Federalist, is worthy to be cited on the most weighty occasions. In the eighty-second number of that splendid work, ALEXANDER HAMILTON treated the subject now under review, and treated it in the following

terms:

"The only thing in the proposed constitution, which wears the appearance of confining the causes of federal cognizance to the federal courts, is contained in this passage: The judicial power of the United States shall be vested in one supreme court, and in such inferior courts as the congress shall from time to time ordain and establish.' This might either be construed to signify, that the supreme and subordinate courts of the union should alone have the power of deciding those causes, to which their authority is to extend; or simply to denote, that the organs of the national judiciary should be one supreme court, and as many subordinate courts as Congress should think proper to appoint; in other words, that the United States should exercise the judicial power with which they are to be invested, through one supreme tribunal, and a certain number of inferior ones, to be instituted by them. The first excludes, the last admits, the concurrent jurisdiction of the state tribunals: and as the first would amount to an alienation of state power by implication, the last appears to me the most defensible construction."

"But this doctrine of concurrent jurisdiction, is only clearly applicable to those descriptions of causes, of which the state courts have previous cognizance. It is not equally evident in relation to cases, which may grow out of, and be peculiar to, the constitution to be established; for not to allow the state courts a right of jurisdiction in such cases, can hardly be considered as the abridgement of a preexisting authority. I mean not therefore to contend that the United States, in the course of legislation upon the objects intrusted to their direction, may not commit the