Colonel Humphreys stated that his claim had been examined by the late agent, General Wiley Thompson, and decided _against_ him; but insisted that the decision was wrong, and avowed his ability to show it erroneous by proper proof whenever he should have an opportunity, and again demanded that the slaves should be brought back to Florida, where he could present his proof without trouble. This letter was inclosed in one directed to Mr. Downing, Delegate in Congress from Florida, and by him transmitted to the Secretary of War, and by that officer referred to the Commissioner of Indian Affairs. Thus driven to the wall, the Commissioner of Indian Affairs came out in plain and unmistakable language, asserting the doctrine, that the Government held the power and constitutional right to dispose of prisoners taken in war, whatever their character may be. This doctrine had been eloquently sustained by General Gaines, on the trial in New Orleans. It was the doctrine avowed by Hon. John Quincy Adams in the House of Representatives, during the next session of Congress; but it called down upon him much abuse in that body, and in the Democratic papers of the country. The Commissioner's report to the Secretary of War set forth in distinct language, that the claims of individuals to slaves were precluded by the action of the Government in sending these people West; that they had been captured by the army and disposed of by the Executive, and the action of the Department could not be changed in consequence of individuals claiming them as slaves. In short, he repeated the doctrine advanced by General Gaines at New Orleans. The report also confirmed the policy of General Taylor in disregarding the claims of individuals to persons captured by the army, and was a tacit condemnation of that pursued by General Jessup, and previously sanctioned by the Secretary of War. This report was passed over to the Secretary. That officer (Mr. Poinsett) having received this report, transmitted it to Colonel Humphreys. This drew from that gentleman a still more elaborate argument in favor of his claim, which occupies nearly four heavy pages in documentary form. This was also transmitted to Mr. Downing, and by him passed over to the Secretary of War; but we are not informed whether the Secretary of War replied to this second argument or not. It is, however, important to the truth of history to notice this recognition of the doctrine by a slave-holding Secretary of War, that the Executive in time of war may separate slaves from their masters, and send them out of the country, without regard to the relation previously subsisting between them and their owners. The principle was thus recognized by Mr. Poinsett, although a citizen of South Carolina, acting under the advice and direction of Mr. Van Buren, a Democratic President of the United States.