Some think that Dr. Wigan's doctrine of the brain's being a double organ, its hemispheres working together like the two eyes, accounts for it. One of the hemispheres hangs fire, they suppose, and the small interval between the perceptions of the nimble and the sluggish half seems an indefinitely long period, and therefore the second perception appears to be the copy of another, ever so old. But even allowing the centre of perception to be double, I can see no good reason for supposing this indefinite lengthening of the time, nor any analogy that bears it out. It seems to me most likely that the coincidence of circumstances is very partial, but that we take this partial resemblance for identity, as we occasionally do resemblances of persons. A momentary posture of circumstances is so far like some preceding one that we accept it as exactly the same, just as we accost a stranger occasionally, mistaking him for a friend. The apparent similarity may be owing, perhaps, quite as much to the mental state at the time as to the outward circumstances. ----Here is another of these curiously recurring remarks. I have said it and heard it many times, and occasionally met with something like it in books,--somewhere in Bulwer's novels, I think, and in one of the works of Mr. Olmsted, I know. _Memory, imagination, old sentiments and associations, are more readily reached through the sense of SMELL than by almost any other channel._ Of course the particular odors which act upon each person's susceptibilities differ.--O, yes! I will tell you some of mine. The smell of _phosphorus_ is one of them. During a year or two of adolescence I used to be dabbling in chemistry a good deal, and as about that time I had my little aspirations and passions like another, some of these things got mixed up with each other: orange-colored fumes of nitrous acid, and visions as bright and transient; reddening litmus-paper, and blushing cheeks;--_eheu!_ "Soles occidere et redire possunt," but there is no reagent that will redden the faded roses of eighteen hundred and----spare them! But, as I was saying, phosphorus fires this train of associations in an instant; its luminous vapors with their penetrating odor throw me into a trance; it comes to me in a double sense "trailing clouds of glory." Only the confounded Vienna matches, _ohne phosphor-geruch_, have worn my sensibilities a little.