At seventeen, Louis left Lausanne for the medical school at Zurich. Here he became the friend as well as pupil of Professor Schinz, who held the chair of Natural History and Physiology. He gave young Agassiz a key to his private library, and also to his collection of birds; of course, the love for natural history grew stronger. Both boys, for Auguste had come to Zurich with his brother, were too poor to buy books even when they cost but a dollar a volume. The Swiss minister was saving to the uttermost to pay for board and decent clothes for his sons, to say nothing of books. Therefore the use of Schinz's library was a great favor. Said Agassiz in after years, "My inability to buy books was, perhaps, not so great a misfortune as it seemed to me; at least, it saved me from too great dependence on written authority. I spent all my time in dissecting animals and in studying human anatomy, not forgetting my favorite amusements of fishing and collecting. I was always surrounded with pets, and had at this time some forty birds flying about my study, with no other home than a large pine-tree in the corner. I still remember my grief when a visitor, entering suddenly, caught one of my little favorites between the floor and the door, and he was killed before I could extricate him. Professor Schinz's private collection of birds was my daily resort, and I then described every bird it contained, as I could not afford to buy even a text-book of ornithology. "I also copied with my own hand, having no means of purchasing the work, two volumes of Lamarck's 'Animaux sans Vertèbres,' and my dear brother copied another half-volume for me. I finally learned that the study of the things themselves was far more attractive than the books I so much coveted, and when, at last, large libraries became accessible to me, I usually contented myself with turning over the leaves of the volumes on natural history, looking at the illustrations, and recording the titles of the works, that I might readily consult them for identification of such objects as I should have an opportunity of examining in nature." The boys remained two years at Zurich. One vacation, as they were walking home, the family having moved from Motier to Orbe, they were overtaken by a gentleman who asked them to ride, shared his lunch with them, and took them to their own door. Some days afterward he wrote to M. Agassiz that he had been so impressed by his son Louis that he wished to adopt him and provide for him through life. This request caused great commotion in the little home, for the writer of the letter was a man of wealth in Geneva, but, after careful consideration, both parents and son declined the offer, preferring to struggle with poverty rather than bear separation.