First edition of Helmholtz’s classic paper in which he announced his invention of the “eye-mirror”, one of the greatest events in the history of ophtalmology. With this instrument it was possible for the first time to examine the interior of the living eye. Although crude attempts had been made earlier to see into the eye, it was Helmholtz’s invention of a workable instrument in 1850 and the publication of his monograph in 1851 that laid the basis of scientific ophtalmology. Helmholtz’s invention of the ophtalmoscope arose from an attempt to demonstrate for his class in Königsberg the nature of the glow of reflected light sometimes seen in the eyes of animals such as the cat. When the great ophtalmologist A. von Graefe first saw the fundus of the living eye, with its disc and blood-vessels, his face flushed with excitement, and he cried “Helmholtz has unfolded to us a new world!”. Helmholtz was born at Potsdam and educated in Berlin. As his parents were poor, and could not afford to let him follow a purely scientific career, he became a surgeon in the Prussian army. Helmholtz’s investigations spanned almost the whole field of science, including physiology, physiological optics, physiological acoustics, chemistry, mathematics, electricity and magnetism, meteorology and theoretical mechanics. In 1847 he published his famous paper Ueber die Erhaltung der Kraft, which became one of the epoch-making papers of the century. Collation: Pp 43, (5) including final blank leaf. One plate of the ophtalmoscope, engraved by Afinger after Helmholtz’s drawing. Binding: Uncut in the original yellow printed wrappers. Preserved in a blue folding paste paper box (made by Johanna Röjgård). Provenance: Fritiof Holmgren (1831-1897) professor of physiology at Uppsala, known for his work on colour vision, the introduction of the wool-skein test and his important paper on colour-blindness in its relation to railway and maritime traffic. Erik Johan Widmark (1850-1909), professor of ophtalmology at the Karolinska Institute. References: Garrison-Morton 5866; Lilly, Notable Medical Books, 205; Albert 1032; Hirschberg § 1021, pp 82 ff; Lebensohn, 53 ff.; Rucker, 21-25; Friedenwald, 'The History of the Invention of the Ophtalmoscope’ in JAMA, 38, No. 9, 549-52; Norman 1041. Waller 4294.