reached. We are compelled to take note of it, and in the case of defective recollection the best of all modes is to cease to think about the matter, and in a short time it will appear almost with the intelligence of a messenger bringing something for which he had been sent.
When one has wearied himself, and his perceptions have been somewhat obscured, even though nothing had occurred of the nature of unconscious cerebration, it would not be surprising if after refreshing sleep the first effort of his mind should classify and complete the undigested work of the day before. The dream imagery under which such things are done frequently invests the operation with a mysterious aspect, which, on analysis, appears most natural. I am informed by one of the participants that some time since two gentlemen in Pennsylvania were conversing concerning an intricate mathematical problem. One of them succeeded in its solution by algebraic methods. The other insisted that it could be done by arithmetic, but, after making many efforts, gave up the problem, and retired for the night. In the morning he informed his friend that in the night, while he was asleep, an old Scotch schoolmaster, who had been his instructor many years before, appeared to him and said, "I am ashamed of you that you could not do that sum. It can be worked out by arithmetic, and I will show you how now." And he added that he had immediately done so, and in the morning when he awoke he had put the figures on paper just as his schoolmaster had done in the dream; and there they were, a complete solution of the example.
It was a very impressive dream, but easily explained. It wis a workable problem. The man, ashamed of himself that he could not do it and exhausted with his efforts, had sunk into a troubled
