A prime interest attaches to this work, because, unconsciously, the author has given us, in advance, his repertory of instruments and principles. From the written word we may anticipate the brilliant achievement, while in every case the action may be tested by a reference to the recorded principle. The retirement of Scott places McClellan in a position where he will have neither partner nor censor in his plans and movements. The graceful and appropriate manner in which the old veteran leaves the field, which age and infirmity will no longer allow him to command, is but a fitting prelude to the military rule of one upon whose brow the dew of youth still rests, and who brings to his responsible task the highest qualities, combined with a veneration for the noble virtues and an emulation of the magnanimous career of his predecessor, at once honorable and inspiring. _Spare Hours_. By JOHN BROWN, M.D., Author of "Rab and his Friends." Boston: Ticknor & Fields. 16mo. It has not yet been satisfactorily explained why doctors are such shrewd and genial men, and, when they appear in the literary field, such charming writers. This is one of the curious problems of the day, and undoubtedly holds its own answer in solution, but has not yet seen fit to make an observable precipitate. Perhaps this is because the times are stirring, and the facts cannot settle. A delightful exhibition is made of something extremely good to take, which we swallow unscrupulously: in other words, we can only guess how many scruples, and of what, this blessed medicine for the mind contains. As it is eminently fit for every American to have an hypothesis upon every subject, we might now, with proper recklessness, rush into print with a few unhesitating suggestions upon this singular phenomenon of doctors gifted and graceful with the pen. We observe, at any rate, that it is something independent of climate and locality, and not at all endemic. Otherwise it might be true that the restless and inquisitive climate of the Atlantic coast, which wears the ordinary Yankee to leanness, and "establishes a raw" upon the nervous system, does soften to acuteness, mobility, and racy corrugation in the breast of its natural ally, the Doctor. For autocratic tempers are bland towards each other, and murderous characteristics can mutually impart something homologous to the refining interchange of beautiful souls. Therefore we do not yet know how much our climate is indebted to our doctors. It may be suspected that they understand each other, as the quack and the fool do, whose interests are identical.