310 THE SALMON RIVERS OF SCOTLAND 



the estuaries or bays in which the fish congregate, seem to me 

 to suggest a different cause. One is reminded of the pale- 

 skinned, sightless condition to which fish are reduced when 

 confined too long in aquaria exposed to sunlight. When in 

 Stornoway in 1902, I was informed by a former gamekeeper 

 at Stornoway Castle, the present lessee of the Royal Hotel, 

 that in summers when this disease is really bad, the fish become 

 so helpless that boys stone them and drag them ashore in the 

 neighbourhood of the harbour, but it is evidently unusual for 

 fish to become blind or to die of the disease. Mr. Pople, in 

 sending me the specimens referred to, informs me that he had 

 never seen a fish dead from this cause. The summer of 1905 

 was unusually dry, and one of the specimens sent was described 

 as the worst Mr. Pople had seen during his tenancy. The dull 

 white appearance had developed into a raw, red sore. The 

 significant remark is also made in a letter of 14th August, 

 " although we have had it very dry, it has been more or less 

 cloudy and windy, it (the disease) would have been worse in 

 brilliant sunshine and light east or no wind." One specimen 

 examined by me was killed on 14th August, and represented, 

 I believe, an average state of the peculiarity. The skin was 

 unbroken, the white area being noticeable not only on the 

 crown of the head but to some extent in the occipital region 

 behind the head, it also extends downwards to the operculum, 

 in which region, I am assured, it first appears. It was not 

 noticeable in front of the eye, which organ appeared to be 

 normal and functional. The colour was a dead white, slightly 

 clouded here and there with a bluish tint. Pigment remained 

 in the dorsal region only at the end of the snout and in a patchy 

 manner above the eyes. There was a distinct depression in 

 the region of the cranial cavity above the brain. The fish was 

 otherwise healthy and in splendid condition, with pyloric 

 appendages loaded with fat ; indeed, it may be stated that 

 the disease does not appear to reduce the plump condition of 

 the fish affected. In another specimen received, killed on 24th 

 July, and showing the disease in a more advanced state, no 

 very marked difference was noticeable on the crown of the 

 head, but the white area above the muscular tissue just beyond 

 the head showed the surface broken and ulcerated in three 

 places. The spreading of this condition over the circumscribed 



