Thus quietly engaged in his ichthyological studies, carrying on his work on the fossil fishes, together with that on the fresh-water fishes of Central Europe, he passed nearly a year at home. He was not without patients also in the village and its environs, but had, as yet, no prospect of permanent professional employment. In the mean time it seemed daily more and more necessary that he should carry his work to Paris, to the great centre of scientific life, where he could have the widest field for comparison and research. There, also, he could continue and complete to the best advantage his medical studies. His poverty was the greatest hindrance to any such move. He was not, however, without some slight independent means, especially since his publishing arrangements provided in part for the carrying on of his work. His generous uncle added something to this, and an old friend of his father's, M. Christinat, a Swiss clergyman with whom he had been from boyhood a great favorite, urged upon him his own contribution toward a work in which he felt the liveliest interest. Still the prospect with which he left for Paris in September, 1831, was dark enough, financially speaking, though full of hope in another sense. On the road he made several halts for purposes of study, combining, as usual, professional with scientific objects, hospitals with museums. He was, perhaps, a little inclined to believe that the most favorable conditions for his medical studies were to be found in conjunction with the best collections. He had, however, a special medical purpose, being earnest to learn everything regarding the treatment and the limitation of cholera, then for the first time making its appearance in Western Europe with frightful virulence. Believing himself likely to continue the practice of medicine for some years at least, he thought his observations upon this scourge would be of great importance to him. His letters of this date to his father are full of the subject, and of his own efforts to ascertain the best means of prevention and defense. The following answer to an appeal from his mother shows, however, that his delays caused anxiety at home, lest the small means he could devote to his studies in Paris should be consumed on the road. TO HIS MOTHER. CARLSRUHE, November, 1831.