27 



" Anatomical Museum, University, Edinburgh, CARLISLE. 



" Sir, 6th February 1879. 



" I am in receipt of your note and Inspector's report, also of four 

 " salmon which came safe and in fine condition. 



" I have examined the disease carefully, and find it to be the same as that of 

 " last spring and summer, namely, Saprolegnia ferax, and I am sorry to say 

 " as vigorous and virulent in form as at that time. 



" The Inspector's report is very important, as showing the rapid growth of 

 " the pest, on which we had no previous information. 



" I will send you next week specimens for the microscope of both last and 

 " this year's fungus, so that you may compare them. 



" "With thanks for the specimens, 



" 1 am, &c. 



" J. Dunne, Esq. A. B. Stirling. 



" I will report further when I have examined the viscera, &c. — A. B. S." 



" College, Edinburgh, 

 " Dear Sir, 5th June 1879. 



"In reply to your favour I am sorry to say that I cannot give you any 

 " account, satisfactory or otherwise, of the cause of the so-called salmon 

 " disease. 



" I can only say that the disease is purely parasitic. How, when, and 

 " whence the fungus comes is the whole mystery. I have utterly failed to 

 " propagate the fungus, by the method said by eminent botanists to be a sure 

 " one, namely, from dead flies and spiders, immersed in rain water for a time 

 " ' when a crop of Saprolegnia ferax can be got at any season.' 



" After 10 or 12 days' immersion there is generally a fungus, or mould, 

 " upon the flies, but it has no affinity to the S. ferax. Further, I have tried 

 " to propagate the fungus upon minnows, by direct contact with the fungus 

 " obtained from salmon and other fish, care being taken, if possible, to keep 

 " the fungus alive till put into the water with the minnows, as follows : the 

 " skin with the fungus adhering to it is cut from the salmon or trout, as the 

 " case may be, never allowing it to dry ; it is put in a wide-mouthed bottle 

 " filled with river water and sent on to me, when both skin, fungus, and 

 " water are emptied into the vessel among the fish. The result is nil, the 

 " minnows eat the fungus, nibble the skin, and make a cover of it to hide 

 " under, and remain healthy and fat. This experiment has been tried since 

 " 15th May, and is still continued without result. 



" Until some one discovers the mystery of what the Sap. ferax originates 

 " from, I despair of any knowledge regarding it further than what it does not 

 " originate from. 



" I am, &c. 



" John Dunne, Esq. A. B. Stirling." 



The disease in its early stages begins with the small white spot described by 

 Mr. Nicholson. The white spot appears distinct from the fungus. The fungus 

 may be a separate growth on diseased flesh. The fish injured may contract the 

 fungus more easily than sound fish, but he will not venture to give an opinion 

 on this point. The fact, as far as he knows, is that no fungus is found in the 

 first stages of disease. The first symptom is a small white spot on the nose. 

 All the fish were cut tip and examined, and all were found internally perfectly 

 healthy. Nearly 2,000 of them were examined. 



In the Eden many of the cock kelts die as a usual occurrence after spawning. 

 Has not heard of fungus growing on these fish ; they become putrid. His 

 attention has not hitherto been called to any fungus on ordinary dead kelts. 



The winter of 1877-8 was a mild winter, and the fish could not have been 

 injured by the ice. The theory was that they had been injured by fighting. 

 The clean fish had not fought. It is thought that the disease having got a 

 footing had spread to these fish ; but this theory is contradicted by Mr. Stirling's 

 evidence as to the minnows. 



Believes the disease is infectious. 



The Eden was the first river affected with the disease in England. Did not 

 hear of any disease till the autumn of 1878. Never heard of it in the Derwent 

 in 1877. 



