We cannot agree with our brother Bronson’s disposition of the troublesome question of jurisdiction involved herein.
Our brother begins his analysis by conceding that:
"While this [Court’s previous] holding assumes that a state court has jurisdiction over such a conversion claim, the Court never so determined; the specific issue of jurisdiction was never raised nor addressed.3 (Emphasis added.)
Yet, a few paragraphs later he states:
"Thus, as we held that plaintiff’s claim arose under state law, state courts had jurisdiction over the claim.” (Emphasis added.)
The prior decision never held that plaintiff’s claim arose under state law for purposes of state, as opposed to exclusive Federal, jurisdiction.
In relevant part, the previous opinion of this Court states:
"Plaintiff also asserts that there was sufficient evi*121dence to warrant submission to the jury the question of conversion of patent rights and the mold. We agree.
"The mold being a specifiable, physical chattel can be the subject of conversion; likewise, intangible personal property can also be the subject of conversion. Warren Tool Co v Stephenson, 11 Mich App 274, 298; 161 NW2d 133, 147 (1968), and Tuuk v Andersen, 21 Mich App 1, 13; 175 NW2d 322, 328 (1969). As such, the intangible right to benefit from a patent right can be converted.” Miracle Boot Puller Co, Ltd v Plastray Corp, 57 Mich App 443, 450-451; 225 NW2d 800 (1975). (Footnotes omitted.)
Again, there is no discussion here of jurisdiction. Our brother concedes that "this holding assumes that a state court has jurisdiction over such a conversion claim”. However, as was stated by Justice Cooley in Allen v Duffie, 43 Mich 1, 11; 4 NW 427 (1880), "A point thus assumed without consideration is of course not decided”. On point, and to our minds dispositive, is the following language from City of Stuart v Green, 91 F2d 603, 604 (CA 5, 1937):
"It is contended that the question of jurisdiction was foreclosed by the decision of this court on the former appeal, but, as the question was not raised by any of the parties or decided by the court, we know of no principle in the doctrine of estoppel or the doctrine of the law of the case which relieves us of the duty of considering and determining whether the cause was properly brought in the federal court. The objection is one which cannot be waived, and may be raised by the parties at any time or considered by the court on its own motion. Utah-Nevada Co v Delamar (C.C.A.) 133 F. 113.”
Looking squarely at the question, we are convinced the state court has no jurisdiction to resolve this dispute. While it is clear that the state *122is empowered to hear and resolve "conversion” claims, it is equally clear that this does not resolve the issue before us. Providing for exclusive Federal jurisdiction, as Congress has for patent infringement suits (28 USC § 1338[a]), would be a meaningless exercise if a complaint were not, on its face, one for which there would otherwise be concurrent state jurisdiction. The very function of the exclusive Federal jurisdiction statute is to oust any concurrent state jurisdiction. Therefore, our starting point must be whether this suit was one "arising under” the patent law1, for which exclusive jurisdiction is vested in the Federal courts.
In 60 Am Jur 2d, Patents, § 4, p 335, it is stated:
"An inventor has no common-law right to a monopoly of his invention. He has the right to make, use, and vend his own invention, but if he voluntarily discloses it, such as by oifering it for sale, the world is free to copy and use it with impunity. A patent, however, gives the inventor the right to exclude all others. As a patentee, he has the exclusive right of 'making, using, or selling the invention throughout the United States.’ The right to 'make’ within the meaning of the patent law embraces the construction of the thing invented; the right to 'use’ embraces within its meaning the right to put into service any given invention; and the right to 'sell’ secures to the inventor the exclusive right to transfer the title for a consideration to others; in these exclusive rights to make, use, and sell, fairly construed, reside the extent of the patent monopoly under the statutes of the United States.”
The conduct alleged in the count for "conversion of patent rights” was wrong only by virtue of the Federal patent law. Therefore, this claim was one "arising under” the patent law and the state court had no jurisdiction to consider it. We hold that it was error to allow it to go to the jury. Because the *123jury returned a general verdict, and it is impossible to tell whether it rested upon the conversion claim or one of the other claims, we reverse and remand for a new trial. See Rock v Derrick, 51 Mich App 704, 709; 216 NW2d 496 (1974), lv den, 391 Mich 836 (1974). Costs to appellant.
C. J. Byrns, J., concurred."Defendant did not file a brief in that appeal.”