Now for the first time the paths of the two brothers separated, Auguste returning from Zurich to Neuchatel, where he entered into business. It chanced, however, that in one of the first acquaintances made by Louis in Heidelberg he found not only a congenial comrade, but a friend for life, and in after years a brother. Professor Tiedemann, by whom Agassiz had been so kindly received, recommended him to seek the acquaintance of young Alexander Braun, an ardent student, and an especial lover of botany. At Tiedemann's lecture the next day Agassiz's attention was attracted by a young man who sat next him, and who was taking very careful notes and illustrating them. There was something very winning in his calm, gentle face, full of benevolence and intelligence. Convinced by his manner of listening to the lecture and transcribing it that this was the student of whom Tiedemann had spoken, Agassiz turned to his neighbor as they both rose at the close of the hour, and said, "Are you Alex Braun?" "Yes, and you, Louis Agassiz?" It seems that Professor Tiedemann, who must have had a quick eye for affinities in the moral as well as in the physical world, had said to Braun also, that he advised him to make the acquaintance of a young Swiss naturalist who had just come, and who seemed full of enthusiasm for his work. The two young men left the lecture-room together, and from that time their studies, their excursions, their amusements, were undertaken and pursued in each other's company. In their long rambles, while they collected specimens in their different departments of Natural History, Braun learned zoology from Agassiz, and he, in his turn, learned botany from Braun. This was, perhaps, the reason why Alexander Braun, afterward Director of the Botanical Gardens in Berlin, knew more of zoology than other botanists, while Agassiz himself combined an extensive knowledge of botany with his study of the animal kingdom. That the attraction was mutual may be seen by the following extract from a letter of Alexander Braun to his father. BRAUN To HIS FATHER. HEIDELBERG, May 12, 1826. . . .In my leisure hours, between the forenoon and afternoon lectures, I go to the dissecting-room, where, in company with another young naturalist who has appeared like a rare comet on the Heidelberg horizon, I dissect all manner of beasts, such as dogs, cats, birds, fishes, and even smaller fry, snails, butterflies, caterpillars, worms, and the like. Beside this, we always have from Tiedemann the very best books for reference and comparison, for he has a fine library, especially rich in anatomical works, and is particularly friendly and obliging to us.