Just as we find a mathematical rule at the bottom of many of the bodily movements, just so thought may be supposed to have its regular cycles. Such or such a thought comes round periodically, in its turn. Accidental suggestions, however, so far interfere with the regular cycles, that we may find them practically beyond our power of recognition. Take all this for what it is worth, but at any rate you will agree that there are certain particular thoughts that do not come up once a day, nor once a week, but that a year would hardly go round without your having them pass through your mind. Here is one that comes up at intervals in this way. Some one speaks of it, and there is an instant and eager smile of assent in the listener or listeners. Yes, indeed; they have often been struck by it. _All at once a conviction flashes through us that we have been in the same precise circumstances as at the present instant, once or many times before_. O, dear, yes!--said one of the company,--everybody has had that feeling. The landlady didn't know anything about such notions; it was an idee in folks' heads, she expected. The schoolmistress said, in a hesitating sort of way, that she knew the feeling well, and didn't like to experience it; it made her think she was a ghost, sometimes. The young fellow whom they call John said he knew all about it; he had just lighted a cheroot the other day, when a tremendous conviction all at once came over him that he had done just that same thing ever so many times before. I looked severely at him, and his countenance immediately fell--_on the side toward me;_ I cannot answer for the other, for he can wink and laugh with either half of his face without the other half's knowing it. ----I have noticed--I went on to say--the following circumstances connected with these sudden impressions. First, that the condition which seems to be the duplicate of a former one is often very trivial,--one that might have presented itself a hundred times. Secondly, that the impression is very evanescent, and that it is rarely, if ever, recalled by any voluntary effort, at least after any time has elapsed. Thirdly, that there is a disinclination to record the circumstances, and a sense of incapacity to reproduce the state of mind in words. Fourthly, I have often felt that the duplicate condition had not only occurred once before, but that it was familiar, and, as it seemed, habitual. Lastly, I have had the same convictions in my dreams. How do I account for it?--Why, there are several ways that I can mention, and you may take your choice. The first is that which the young lady hinted at;--that these flashes are sudden recollections of a previous existence. I don't believe that; for I remember a poor student I used to know told me he had such a conviction one day when he was blacking his boots, and I can't think he had ever lived in another world where they use Day and Martin.