56 SALMON FISHING IN THE TWEED 



regaining their natural colour when placed in the 

 sun. From these circumstances, observed also in 

 some species of other genera, Dr. Stark is led to 

 infer that fishes possess, to a certain extent, the 

 power of accommodating their colour to the ground 

 or bottom of the waters in which they are found. 

 The final reason for this may be traced to the 

 protection such a power affords to secure them 

 from the attacks of their enemies, and exhibits 

 another beautiful instance of the care displayed by 

 Nature in the preservation of all her species. Dr. 

 Stark often observed that on a flat, sandy coast 

 the flounders were coloured so very much like the 

 sand, that, unless they moved, it was impossible to 

 distinguish them from the bottom on which they 

 lay.' 



"Mr. Shaw, who has the charge of the salmon 

 cruive at Drumlanrig, has observed that the salmon 

 taken in it change their colour in consonance with 

 the turbid or refined state of the water. In the 

 experiments he has made with parr in diflerent- 

 coloured earthenware vessels, the change of colour 

 is perfected in the space of four minutes. If parr 

 is taken from the dark-coloured vessel, and put 

 immediately to the parr in the light-coloured one, 

 the difference of colour between the two fish will 

 be found strikingly observable. 



"Mr. Scrope himself had observed that the 

 trout at Castle Combe are white in a chalky spate, 

 resuming their colour when the water clears ; and 

 that in all the rivers in which he had fished, the 

 fish are clear in a gravelly bottom, and dark in 

 that overhung with trees. All this he considered 



