"Can a man (white) be permitted to receive the priesthood, who has a wife who is either black or is tainted with negro blood?"
President [George Q.] Cannon said he had understood President [John] Taylor to say that a man who had the priesthood who would marry a woman of the accursed seed, that if the law of the Lord were administered upon him, he would be killed, and his offspring, for the reason that the Lord had determined that the seed of Cain should not receive the priesthood in the flesh; and that this was the penalty put upon Cain, because if he had received the priesthood the seed of the murderer would get ahead of the seed of Abel who was murdered. The point, President Cannon said, which President Taylor sought to make was that if a white man who had received the priesthood should have children by a negro woman, he could go back and act for his dead ancestors on his wife's side, and he therefore thought it would be improper for a man, as for instance the case referred to, to receive the priesthood for the reasons assigned as being those given by President Taylor.
While there was no formal action taken, this seemed to be the mind of the Council, President [Lorenzo] Snow adding that the way might be opened for the man referred to in the case under consideration to get a divorce from his present wife and marry a white woman, and he would then be entitled to the priesthood.
[Marquardt, H. Michael, Mormon Central: Excerpts From Minutes of the Council of the Twelve and of the First Presidency, 1879-1947, George Albert Smith Papers, Manuscripts Division, Marriott Library, University of Utah, http://www.xmission.com/~research/central/chorg2.htm]