And, after all――what are “the Blues?” Everything else has been classified, analyzed, and reduced to scientific system; and why not these beings which figure so largely in the history of the human mind? This is a subject of profound inquiry, and I wonder it has not attracted the attention of the philosophical. Let us look at it. To get firm hold of the subject, we must suppose a case. I sit in my room alone. Alone, did I say? As nature abhors a vacuum, the mind instinctively shrinks from solitude. If fleshy forms are not present, a host of imps press in from crack and crevice, to gambol around us. The mind is like the room in which the body is held, and these shadowy elves issue forth from the plastering of the walls, or peep out from the dark arras that hangs betwixt the visible and invisible world. Could we break through the plastering, or lift the arras, and see what these seeming imps are――whether they are things, or only images of things; whether they are substantial spirits, which, like invisible eels in water, are ever playing their pranks behind the curtain of vision; could we do this, our task would easily be done; and for our discovery we should expect to be made a member of some philosophical society. But, alas! there is no bridge that crosses the gulf between life and death――none, at least, upon which a being of flesh and blood can return. It is therefore impossible to follow “the blues” to their retreats――to the recesses from which, unbidden, they come, and to which, pursued, they fly. What, then, are “the Blues?” In natural history, there is nothing like dissection. But, before dissection, we must have a subject. How, then, shall we catch a blue?――that is the first question. The easiest way is to take one by supposition, and, while we are supposing, we may as well include the whole race. These can be arranged as follows: ORDER I. THE BLUES. These have no head, no heart, no ears, no breathing organs; body, invisible; food, the human heart. {CLASS I. Blues of reverie: { pleasing, but not to be too { much indulged. { _Order I._ {CLASS II. Rum blues: pestiferous. _The Blues._ { {CLASS III. Blues of indigestion: { horrible. { {CLASS IV. Blues of bad { conscience: frightful. We might now proceed to give the several kinds into which each class is divided, and then the numerous species of each kind. But this must be reserved for some future work on the subject; and if we should publish such an one, let no person laugh at our labors, nor sneer at our philosophy. “The Blues” constitute a great subject of scientific research, and are by no means unworthy of the moral philosopher. We have only time to make a few observations, to show the force of this latter remark.