The interest expressed in the Emigration question has determined the brief review we here give, and which we may continue next week, of Mr. Gaines' last letter against en masse emigration. The letter in question would have received earlier attention, had not a press of duties made it impossible. In attempting the slightest examination possible, and yet, the most extended under the circumstances, it cannot be supposed that a defence of the en masse theory will be given, other than incidentally, as "Gaines," by avoiding the issue, has left nothing for us to defend. Neither can we be expected to wade through "Shakspeare and the Ancients," to present to our readers a conglomeration, equalled only by Sue's nondescript dish, as a proof of our position, when the contradictory positions taken by Gaines, himself, furnish material for the refutation needed.

  The first point made is, that the Fugitive Slave Law is a blessing.

  If the law in question has been ignored by the people, if the anti-slavery sentiment of the North is strong enough to make it void why is it necessary for fugitives to proceed to Canada, or why does not the anti-slavery feeling protect them? If every one who voted for the repeal of the Missouri Compromise were doomed to remain at home after the next election, that fact would furnish no evidence of an anti-slavery sentiment in this case. The rights of white men had been invaded; a solemn compact entered into with white Americans had been broken; the people when opposing its operation, only attempted to shew their sense of the injustice done them. Mr. Gaines knows full well that the strongest Anti-Nebraska advocates are those who, like Horace Greely, "want no more ebony editions, no more black republics;" those who say, give them "the whole of the West Indies," if you please, but at all events, get them off the continent; that is the kind of Anti-Slavery sentiment which has been called forth,—a kind which has always existed,—that which defends the colored man, incidentally, if at all, when the rights of white men are invaded; the kind which assumed renewed activity by the passage of the Fugitive Slave law. Who will say that the people of the North were not cognizant of the fact, that the system of slavery, as carried on at the South, is more injurious in its effects than the Fugitive law? Is the prospective rendition to slavery of persons, with a trial by jury, more horrifying, more wicked than that of keeping millions in such a state? Are the proceedings of the United States Commissioners any more farcical, any more wicked?—are the Marshalls and their aids any more despotic?—are they invested with any more, with as much power as the master, from which the Fugitive escapes? Is the agony of mind experienced by the fugitive, from the time of his arrest to the period of his delivery to his master, any more intense than that experienced by the slave, on his journey northward? What then constitutes the abominable feature of that much talked of law? Is it not that those apprehended will not have the benefit of trial by jury-not that they shall be "delivered up on claim," but that they are to be plunged into American slavery—that "sum of all villanies;" this constitutes its soul-crushing feature.

  Having, therefore, before us the fact of a state of oppression into which those coming under the influence or within the reach of the Fugitive law can be plunged, it is that, we maintain, which gives character to it, and which at the same time enables us to prove the truth of the assertion, that it is only an indignant feeling at the invasion of the rights of white men, which has caused the demonstrations against the law throughout the "Union," whenever and wherever they took place. Colored men's rights had been disregarded for centuries; the system of slavery, in all its horrors, was unheeded; but the moment that the Fugitive law was proclaimed, denying Northern men the right to extend the hand of charity to whoever they please, or commanding them on penalty to aid in enforcing it, then came the opposition of men who felt their rights invaded. Any one taking the trouble to look over the proceedings of meetings on that subject, and the papers published at that time, will bear witness to the correctness of our views.

  Mr. Gaines' "parody on his Saxon story, will not be received in the sense in which he intends it. Northern men "are proud of the abolition name," when they have judgment enough to discern their own interests, and know that the term will be so understood.

  The Uncle Tom literature, so triumphantly brought forward, with which to cap the climax, on northern sentiment, so far from proving a regard for the colored man, is another evidence of our position. In most of those works the heroes and heroines are nearly white; their fair complexion and flowing locks are made to stand forth as the prominent feature of the picture. That northern sympathy is enlisted more readily when "white fugitives" come among them, is a subject of frequent remark; let a dozen blacks pass northward, and the fact may be recorded; but the advent of one in whose lineaments Saxon parentage can be clearly traced, gives free play to the abolition sentiment of more than ninety one-hundredths of the papers devoted to "black manity." Uncle Tom's Cabin, deemed the greatest of its kind, is a clear exponent of SUCH liberal tendencies. Uncle Tom, the representative of the black man, has the position thought to be the best for his class: he suffers, submits and dies. George Harris who represents the mixed races, rebels, escapes, and flies to a land, on this continent, where freedom reigns; but is suddenly seized with a desire to labor in a "greater field of usefulness" (?)—although more nearly allied to the European, he must go to the land of his fathers, (?) to assist in regenerating it.

  Superficial observers may be carried away by specious appearances, but diligent searchers after the causes of things, cannot fail to be convinced of the truthfulness of our remarks. If a genuine regard for the colored man is so universal, how does Mr. Gaines account for the secret combinations which are now numerous all over the northern States, for the purpose of paralyzing the efforts of colored persons to acquire real estate, and to keep lucrative employments beyond their reach? We do not look for an answer to this question, but suppose that Mr. Gaines will say: "All men are born free and equal; but it does not follow that all men are equal in a state of society"—a reply having as much connection with the present question, as the one to which it was given. We asked Mr. Gaines a direct question; we wished to know why the colored higher classes in the States did not associate with whites of the same class? but when we look for a direct answer, there stands the quotations above given which is a fair specimen of Mr. G.'s method of reasoning.

  When Mr. G. began his series, we supposed that he was going to enlighten us on the subject of an en masse emigration to Canada, we were waiting to see reasons in proof of the fallacy of the doctrine; but they did not appear; the whole series, with the exception of the concluding part of the last, is occupied with a one-sided view of the States, and an attempt to make intelligent readers believe that Canada is in no better condition than the States. Talk of colored Canadians needing a certain combination of circumstances to elevate them, they are already elevated; they have only to go on progressing as do those around them; the moment they set foot on the soil, they stand up as British freeman; who can be more elevated?—that moment they stand as highly elevated above the colored men of the States as British liberty is in advance of American liberty.

S.