On the photochemistry of the retina and on visual purple / translated from the German of W. Kühne ; edited, with notes, by Michael Foster.

  • Kühne, W. (Willy), 1837-1900.
Date:
1878
Catalogue details

Licence: Public Domain Mark

Credit: On the photochemistry of the retina and on visual purple / translated from the German of W. Kühne ; edited, with notes, by Michael Foster. Source: Wellcome Collection.

Provider: This material has been provided by UCL Library Services. The original may be consulted at UCL (University College London)

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    PEEFACE. It is now more than twelvemonths since I undertook to pub- lish an English translation of Prof. Kiihne's treatises on The Photochemistry of the Retina and on Visual Purple. Circum- stances 'over which I have had no control' have, until now, prevented my intention from being accomplished. Meanwhile further investigations have largely changed the aspects and the prospects of the subject. When Boll first announced his discovery of the sensitive purple colour of the retina he ex- pressed the very natural conviction that it was directly con- nected with the act of vision; and, as will be seen from the following pages, the earlier results obtained by Kiihne promised at first to afford a facile solution of many visual problems. As, however, thanks to the energetic labours of this latter observer1 and his talented assistant Dr A. Ewald, rapid pro- 1 As the reader is possibly aware, Kiihne has in some quarters been re- proached for having made use of Boll's discovery. To Boll must undoubtedly be given the credit of the discovery that the retinas of many animals possess a sensitive purple colour (for the mention of it by previous observers (see p. 15) does not amount to a discovery), and he therefore will rightly share in all the fame belonging to tbe subsequent developement of that discovery. At the samo time the study of Boll's writings can leave no doubt on the mind of the candid reader that at first Boll did not realize that the visual purple undergoes