84 APPENDIX 



During the month of March, and until the 17th April, angling was, I believe, at- 

 tended with more success than has been usual of late years: two or three fish were 

 usually killed every day, and often more. Of these fish, I saw about a dozen at diffe- 

 rent periods, and was able to observe on almost every one bruises, or some marks of 

 slight injury. Several fish (I think I saw three) were also badly wounded, and it was 

 an accepted opinion among the anglers that porpoises or otters may have bitten them, 

 which, as the wounds were so large, seemed probable, though on this point I am not 

 qualified to give an opinion. 



From the 21st to the 23rd April flood water was prevalent, and many fish were 

 killed with the rod. On the 26th April several fish were caught by nets in the river, 

 and I was shown one or two that had suspicious marks, and as though fungus had 

 grown on them, but these wounds were all thoroughly cleaned of all outer growths by 

 the fishes' struggles in the nets. I took several small cuttings of what appeared dis- 

 eased skin home with me, and, remembering my previous failures to obtain growths 

 from such cuttings, I mounted an arrangement to admit a constant stream of water on 

 the pieces offish skin that, attached to a hair and submerged, were under observation. 

 After two days I was able to observe a good growth of Sap. ferax on two of the pieces, 

 but it did not appear on all of them (no doubt, partly because my means of ob- 

 taining the constant stream of water was difficult, and needed continual watching, for 

 want of proper appliances and pipe water). On taking out the growths, and removing 

 them to a warmer locality in a separate vessel, the development of the fungus was 

 greatly increased, but was quickly overtaken and suppressed by other forms of organic 

 life, which developed so quickly as to render the water quite turbid and ill-smelling in 

 a short time. The Saprolegnieae then, of course, went to the bad, but not before I had 

 had several microscopical observations of it, and had quite satisfied myself as to its 

 identity. 



On the 30th April I had a confirmatory observation of exactly the same kind, from 

 small portions of the deceased skin of another fish caught also by nets in the river, the 

 fungus again developed under running water and gave as before plenteous zoospores. 



I venture to think these observations show that the fish from which the cuttings 

 were taken had been attacked by the fungus, but that the growth was not sufficiently 

 quick to cause the fish to die, and I am forced to believe that with the water becoming 

 colder they might have recovered, or that with water constantly at say 45 ° Fahr., the 

 disease would not have develped on them to a dangerous extent, as the disease in its 

 worst form did not break out until a fortnight later, when the conditions in the river 

 were changed, the water being then quite low, and its heat nearly 60* Fahr. 



The 5th May was the first really warm day that we had here this year. By 

 the 7th of May the water registered 57^° Fahr., and the weather continued warm 

 and dry. I had observed last year that the water was at about 56 when the disease 

 broke out, and therefore (allowing about four days for the disease to develop) I thought 

 we should hear of the usual outbreak on about the nth of the month, and made notes 

 to this effect. On the 12th I heard of the first diseased fish being seen, and on the 

 14th I was called at my special request to see the first fish that, thoroughly diseased, 



