Published online by Cambridge University Press: 11 May 2009
An account is given of the effects of changes of concentration of salts in the ambient medium on the colours reflected by the scales of herring and salmon. These lead to the conclusions (1) that in the herring in life the reflecting cells which lie under the scales and outside the scale pocket are in osmotic equilibrium with the external medium and not with the fish's body fluid (2) that the corresponding cells which lie inside the scale pocket of herring are always in equilibrium with these body fluids (3) that in the salmon all parts of the scale, including the parts outside the scale pocket, are in equilibrium with the internal body fluid and osmotically protected from the external medium.