Arthur. — On Diseased Trout in Lake Wakatipu. 201 



stage or without cells, and the cells themselves were exceedingly minute, 

 just visible clearly under a two -inch objective. A subsequent examination 

 made since returning to town (the fungus meanwhile having been preserved 

 in glycerine and boracic acid) gave similar appearances, but no Ogonium. 

 It, however, revealed the fact of the spores being contained really in an 

 inner sac or tube, the space between which and the outer covering of the 

 main sac appeared to be full of a colourless fluid. From the appearance of 

 this trout and that of others in the shoal from which it was taken, it is 

 manifest that these fish are in a chronic state of disease, and that not con- 

 fined to this the spawning season, for I have ascertained the presence of 

 fungus at other times, as in the month of March of this year. And here it 

 may be observed in passing that fungus has been found on trout at the 

 Wallacetown ponds in 1876, and recently a Marlborough gentleman told 

 me of his taking out of some still pools in a stream in that district 

 fungussed trout years ago, while our native fish the Galaceias and silver fish 

 are not always free from it. At the same time the identity of the fungus 

 among all those fish has not been determined. A consideration of the 

 above facts naturally suggests two questions, first, ivhat is the cause of, and 

 second, what the cure for, the fungoid disease in the Wakatipu trout. 

 The Cause of the Disease in the Wakatipu Trout. 

 In the first place, so many difficulties surround the investigation, that 

 the cause or causes of the disease cannot well be presumed to be stated 

 exhaustively. At the same time, so far as our knowledge of the habits of 

 trout and of the conditions necessary to their healthy life enable us to 

 judge, we are warranted at least in advancing an opinion. I assume then 

 that the trout in Queenstown Bay were spawned in the Town Creek, a stream 

 far too small for the subsequent accommodation of the size of fish to which 

 these attain. Growing too large for this stream they have naturally 

 dropped down to the lake during floods, and when there have so increased 

 in size in the course of a few years as to become physically incapable of 

 again ascending the stream at their regular spawning season. No stream 

 large enough seems to be sufficiently near, and the great depth of water 

 along the shore to the west, without leading shoals, tends to confine the 

 trout so to speak to one place, or at least to operate against their migration 

 in that direction. In this respect the Wakatipu is totally different from the 

 streams where the progenitors of our trout live in England, where the water 

 does not probably have a greater average depth than four feet. With the 

 true instincts of the Salmonidae, however, the trout in Queenstown Bay 

 linger near their parent stream, unable so to speak to convince themselves 

 how it is they cannot be again admitted, and, diseased as they have become, 

 presenting an appearance suggestive of the lame and sick folk of old who 



