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Craigend, Stirling, Saturday, October 4th, 1879. 



Present : 



Archibald Young, Esquire. 



Sir James R. Gibson Maitland, Baronet, Craigend, Stirling. — Thinks CRAIGEXD. 

 in early cases the fungus is not the disease but an aftergrowth. The disease 

 can exist to a fatal extent independently of the fungus. There cannot be 

 fungus on a perfectly healthy fish. There must be, under ordinary circumstances, 

 previous debility. There cannot be the fungus without the presence of one 

 of three conditions : — 1. A want of healthy slime on the scales. 2. Injury. 

 3. Excreta of parasites. The disease may kill hy suffocation. Has known it kill 

 in 60 hours. The diseased white spot is the result of debility. Does not 

 consider the disease to be in any sense contagious, although many fish with 

 fungoid growth would undoubtedly increase the number of germs of fungus 

 to the cubic foot of water. Overstocking is not the cause of the disease. All 

 the Lochleven trout (about 12,000) now in the three large ponds here were in 

 the three small 130-feet ponds during the last winter. These ponds were 

 completely frozen over from December to February, and were not perfectly 

 free from ice from the 1st March. The ice during most of the time was over 15 

 inches thick. A small hole about 2 feet in diameter was broken in the centre 

 of each pond every morning. The loss of fish from November to March, under 

 these circumstances, was only one per 1,000. The trout in these ponds were 

 from half a pound to five pounds inweight, and were hatched in 1875, 1876, and 

 1877- 



Thinks that the salmon disease may be communicated from one water- 

 shed to another, where the head waters of the rivers are in close proximity, by 

 birds carrying the germs of predisposing causes, be they seeds of vegetable 

 growth or zoospores of fungoid growths, but does not consider that feeding 

 on diseased fish would render them more liable to do so. Thinks that some 

 well-informed local official should have discretionary power, with the consent 

 of the Salmon Commissioners, to remove diseased fish from the water; all 

 dead fish should undoubtedly be removed at once and buried above flood-water 

 mark. 



The circumstances and facilities of returning to the sea vary so much 

 in different rivers and in different parts of the same river that no hard-and-fast 

 rule can be laid down. It seems to be an economical question whether, in the 

 case of the Commissioners coming to the conclusion that all diseased fish 

 should be removed, those slightly diseased might not be sold for food, in 

 accordance with the evidence of Sir Robert Christison and others, and the 

 proceeds applied to the expense of stamping out the disease. Personally 

 holds no opinion on this point. In all cases of disease that have come under 

 his observation the fish died where the bleeding sore occurred. Considers 

 that the vigorous application of bay salt removed the cause, but did not cure 

 any advanced stage of the disease itself. Will, however, make further 

 experiments next season. 



It is certain that exceptional circumstances of temperature and rainfall will 

 affect the causes of the disease ; the extraordinarily rapid vegetation of an 

 Alpine region is a proof of the effect of a severe winter on the growth ef algce 

 and other water plants. 



Thinks that probably the action of rainfall is confined, first, to the modifica- 

 tion of temperature ; second, to increasing or decreasing the facilities for the 

 passage of .fish ; third, to the destruction of algae by depositing mud from the 

 neighbouring lands. The common green frog-spittle which grows on the 

 banks of ponds may be exterminated in a few days by raking up the mud. 

 Rainfall may also act in a secondary manner by its necessary accompaniment 

 of cloud, absence of strong light being unfavourable to the growth of water 

 vegetation. Cloud is also a possible vehicle for fungoid germs. 



Feels great diffidence in offering an opinion on Dr. Crosbie's letter on the 

 salmon disease, handed in by Mr. Stoddart at Kelso. The description of the 



P712. F 



