Letters from men outstanding in the scientific field, including Berzelius, Darwin, Faraday, Guericke, Helmholtz, Jenner, and Leibnitz. Some were presented to Dr. Herter by Henrietta Darwin Litchfield, daughter of Charles Darwin, and some by Paul Ehrlich to whome a number of the letters are addressed. Included in the collection is one page of the autograph manuscript of Darwin's ORIGIN OF SPECIES, authenticated by his daughter.