He had been 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 is work aside at last and tried to dismiss it from his mind. Shortly after, he waked one night persauded that while asleep he had seen his fish with all the missing features perfectly restored.
"He went early to the Jardin des Plantes, thinking thaty on looking anew at the impression he would see something to put him on the track of his visin. In vain -- the blurred record was as blank as ever. The next night he saw the fish again, but when he waked it disappeared from his memory as before. Hoping the same experience might be repeated, on the third night he placed a pencil and paper beside his bed before going to sleep.

"Towards morning the fish reappeared in his dream, confusedly at first, but at last with such distinctness that he no longer had any doubt as toits zoological characters. Still half dreaming, in perfect darkness, he traced those 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 would 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 portions of the fish proved to be hidden. When wholly exposed, the fossil corresponded with his dream and his drawing, and he succeeded in classifying it with ease."