It is interesting both as psychological fact and as showing how, sleeping and waking, his work was ever present with him. He had been for two weeks striving to decipher the somewhat obscure impression of a fossil fish on the stone slab in which it was preserved. Weary and perplexed he put his work aside at last, and tried to dismiss it from his mind. Shortly after, he waked one night persuaded that while asleep he had seen his fish with all the missing features perfectly restored. But when he tried to hold and make fast the image it escaped him. Nevertheless he went early to the Jardin des Plantes, thinking that on looking anew at the impression he should see something that would put him on the track of his vision. In vain--the blurred record was as blank as ever. The next night he saw the fish again, but with no more satisfactory result. When he woke it disappeared from his memory as before. Hoping that the same experience might be repeated, on the third night he placed a pencil and paper beside his bed before going to sleep. Accordingly toward morning the fish reappeared in his dream, confusedly at first, but at last with such distinctness that he had no longer any doubt as to its zoological characters. Still half dreaming, in perfect darkness, he traced these characters on the sheet of paper at the bedside. In the morning he was surprised to see in his nocturnal sketch features which he thought it impossible the fossil itself should reveal. He hastened to the Jardin des Plantes, and, with his drawing as a guide, succeeded in chiseling away the surface of the stone under which the portions of the fish proved to be hidden. When wholly exposed, it corresponded with his drawing, and his dream, and he succeeded in classifying it with ease. He often spoke of this as a good illustration of the well-known fact that when the body is at rest the tired brain will do the work it refused before. Hilprecht's Sleep Vision.--Quite as surprising a dream was that of Prof. Hilprecht, of the University of Pennsylvania. He had been trying for some time to decipher certain characters on ancient cylinders from the Orient. In spite of much hard mental labor he had been utterly unable to reach definite conclusions. In the midst of work on the subject he dreamt one night that a priest of the olden time appeared to him and read off the inscription that he had in vain been trying to decipher. Immediately after waking he told his wife of his dream and wrote down the interpretation that had thus been given. It was quite different from anything that he himself had obtained any hint of in his previous studies. When he got back to the inscription he found that this interpretation would satisfy the conditions better than any other, and there seemed no doubt that it represented the missing solution. {138}