Important News from St. Domingo—Progress of General Annexation.

The news which we have received here, during the last two days, by two vessels from different ports of the Island of San Domingo, or Hayti, in the West Indies, and which will be found in this day's paper, is of the highest importance to this country for all time to come.

Through the energy and industry of a special agent and correspondent, whom we sent to San Domingo, last summer, we have received, exclusively, copies of several documents and diplomatic correspondence which have already passed between the government of the United States and that of San Domingo, preparing the way for the great measure of the recognition of the latter republic by the former, according to the same policy or plan, which was pursued towards Texas, and which has, in a few years, terminated in the absorption or annexation of the latter into this great republic of the North. These documents consist of a memorial presented to the United States government at Washington, by the agent of San Domingo, about a year ago, together with copies of highly interesting letters, written by certain public agents sent to San Domingo, during last summer—one of them by Mr. Hogan, the agent of the United States, then in San Domingo, to which island he was sent by Mr. Calhoun, then Secretary of State, in order to investigate the resources, and ascertain the disposition and capabilities of that new republic in the West Indies.

Thus far, the movement has been highly prosperous and successful. The war between San Domingo and Hayti, is fast drawing to a close, and it is highly probable that the black and bloody republic will be overcome by the white and more civilized race of San Domingo. As soon as that object shall have been accomplished, there will come other movements, leading to the natural termination of the negotiation, already begun, in annexation to the United States.

We have long perceived that the diplomatic correspondence which we give, only comes up to the period at which Mr. Hogan, the United States agent, left the island, during last summer; but what Mr. Hogan, the United States agent, has already made to the Secretary of State at Washington, or the action of our government on that information, has not transpired. What the present President or his Secretary of State may have in contemplation on this subject, we know not; but we have reason to believe that the present President has not failed to take notice of the diplomatic movement of Mr. Calhoun, or the reports of Mr. Hogan, which he has so auspiciously begun in the annexation of Texas.

Looking around, we see, that the United States, favored by God and nature, is surely marching, with a step as regular as the eternal laws of nature, to its destined and ultimate extent; that there is her to fulfil—that is, the union and incorporation, in one great and mighty system, or one immense confederacy of regular republics, the whole of the continent of North America, with the islands around it, of which Hayti is one. We see that, at any rate, in Canada, the spirit has been awakened that will, in the course of a few years, lead to the republic of the Great North; and we see that the differences between England and the United States, respecting the 49th parallel in the Oregon Territory, in a short time will terminate in a manner long since contemplated and begun in reference to other portions of this continent, but as yet not united to this republic. Our government ought, in our view, to quietly settle that question by giving England all she asks or desires in the North—and a quarter of a country, all Oregon will, like a ripe fruit, fall into the lap of the United States, along with every other state or island of the North. The desirable end of all prosperity, peace and stable government in San Domingo, in Mexico and in the neighboring countries, will be reached by the coming events that already cast their shadows over the present and the future, and make the monarchies of the Old World look aghast.

The next news from San Domingo will be highly interesting, and we wait for it, through our special agent and correspondent, now in that island, with every probability of its being decisive of great events. With our special agents, both in San Domingo, in Cuba and in Mexico, we have already dispatched special correspondents to both these countries, to gather information and transmit news of great importance, even in advance of our own government at Washington.