1828-1829: AGE 21-22.
First Important Work in Natural History.--Spix's Brazilian Fishes.
--Second Vacation Trip.--Sketch of Work during University Year.
--Extracts from the Journal of Mr. Dinkel.--Home Letters.--Hope of
joining Humboldt's Asiatic Expedition.--Diploma of Philosophy.
--Completion of First Part of the Spix Fishes.--Letter concerning
it from Cuvier.