The whole argument for the existence of colour perception in the salmon is, therefore, undoubtedly a strong one.
(1) It behaves as if it sees differences in colour.
(2) It is possible for its eye to get a proper view of an object within a certain area on the surface of the water.
(3) Its retina is of a sufficiently highly developed type to admit of its being differently influenced by different parts of the colour spectrum.
R. Marcus Gunn, F.R.C.S.
The writer of this paper, Mr. Marcus Gunn, is an acknowledged expert as an oculist. His opinion, therefore, on the subject of the salmon’s visual apparatus is of no ordinary value and should be duly pondered. Perhaps we ought to inform our readers that the eyes of the two salmon which he examined with a view to this paper were extracted from two large fresh run fish caught in autumn by the undersigned—one on the Ythan and the other on the Dee. The eyes were extracted immediately after capture and placed, in one case in chloral, in the other in formalin. Mr. Gunn was thus enabled to make sections of both, with the results embodied in his authoritative paper.
W. Murdoch.