In conclusion, my opinion is, that the decision of the Circuit Court, upon the law arising upon the several pleas in bar, is correct, but that it is erroneous in having sustained the demurrer to the plea in abatement of the jurisdiction; that for this error the decision of the Circuit Court should be reversed, and the cause remanded to that court, with instructions to abate the action, for the reason set forth and pleaded in the plea in abatement. In the aforegoing examination of this cause, the circumstance that the questions involved therein had been previously adjudged between these parties by the court of the State of Missouri, has not been adverted to; for although it has been ruled by this court, that in instances of concurrent jurisdiction, the court first obtaining possession or cognizance of the controversy should retain and decide it, yet, as in this case there had been no plea, either of a former judgment or of _autre action pendent_, it was thought that the fact of a prior decision, however conclusive it might have been if regularly pleaded, could not be incidentally taken into view. * * * * * Mr. Justice CAMPBELL. I concur in the judgment pronounced by the Chief Justice, but the importance of the cause, the expectation and interest it has awakened, and the responsibility involved in its determination, induce me to file a separate opinion. The case shows that the plaintiff, in the year 1834, was a negro slave in Missouri, the property of Dr. Emerson, a surgeon in the army of the United States. In 1834, his master took him to the military station at Rock Island, on the border of Illinois, and in 1836 to Fort Snelling, in the present Minnesota, then Wisconsin, Territory. While at Fort Snelling, the plaintiff married a slave who was there with her master, and two children have been born of this connection; one during the journey of the family in returning to Missouri, and the other after their return to that State. Since 1838, the plaintiff and the members of his family have been in Missouri in the condition of slaves. The object of this suit is to establish their freedom. The defendant, who claims the plaintiff and his family, under the title of Dr. Emerson, denied the jurisdiction of the Circuit Court, by the plea that the plaintiff was a negro of African blood, the descendant of Africans who had been imported and sold in this country as slaves, and thus he had no capacity as a citizen of Missouri to maintain a suit in the Circuit Court. The court sustained a demurrer to this plea, a trial was then had upon the general issue, and special pleas to the effect that the plaintiff and his family were slaves belonging to the defendant.