iOl 



stances as the young salmon, yet no deaths occurred amongst 

 the latter, if we except those very few which exhibited some 

 malformation when first hatched. 



It may be remembered that the trout ova were all placed 

 in a separate wooden trough about eight feet long and one 

 foot wide, through which a gentle stream of water was made 

 to flow ; and up to the first week in September the young fish 

 (about 120, as was supposed) were left in the same trough. The 

 salmon, on the contrary, were long since allowed to escape 

 from their breeding boxes into a series of shallow pools, thus 

 getting increased room and a larger supply of water. A few 

 deformed salmon were found dead at various times, and it is 

 therefore reasonable to suppose that had any of the others 

 died we must (with the careful supervision that has always 

 been kept up) have found them also. 



Upon examination, white patches were seen on the pectoral 

 fins of the trout in the trough, varying in size in different 

 individuals, those which exhibited the largest patches being 

 evidently sickly. Mr. Eead (one of the Salmon Commissioners), 

 after several days close observation, came to the conclusion 

 that when once a fish exhibited the white spot on the fin he 

 never recovered, the disease increasing so rapidly as to kill 

 the fish in three or four days. Twenty fish died in two days 

 when the disease was at its worst. 



The number of trout had been greatly under estimated, and 

 want of room appeared to be the cause of the mischief, a 

 small pond was hastily constructed, and one hundred fish, 

 including all that could be found exhibiting the white spots, 

 were at once removed from the trough and placed in the 

 pond. The result shewed that the conclusions arrived at were 

 correct, as the number of fish with the white spots decreased, 

 and the percentage of deaths fell rapidly. 



The entrances to and exits from the clearing pond were 

 then covered with perforated zinc, and 180 trout were moved 

 into it, leaving about 40 still in the trough. The fish 

 evidently enjoyed the change, and for several weeks past no 

 deaths have occurred. There were between 30 and 40 lost 

 in all. 



Upon microscopic examination, the white spots were resolved 

 into aggregated masses of filaments, each filament attached 

 by one end to the skin ; in two instances a number of the 

 filaments extended on to the gills of the fish. When detached, 

 the filaments exhibited none of the sucking or hooked apparatus 

 with which the epizoa are invariably furnished, and under a 

 power of 200 diameters each filament was found to consist of 

 a vast number of minute cells, there being no trace of an 

 alimentary canal. I therefore believe them to be of vegetable 

 origin, and it is probable that they were rather the result 

 than the cause of disease. 



The health of the young salmon is all that can be desired. 



