480 Dr KNOX on the Natural History of 



We were now anxious to learn if the fry, whilst under the gravel, 

 or shortly after their escape from it, were exposed to destruction 

 from the trout inhabiting the same streams, forasmuch as very bold 

 assertions had been made on this as well as on most matters con- 

 nected with the history of the salmon. Accordingly, on the 23d 

 and 31st of March, days on which we have seen that the salmon- 

 fry in the state offish might be considered exposed to be devoured 

 by trout burrowing under the gravel for that purpose before the 

 escape of the salmon-fry, or when, just escaped from the gravel- 

 beds in a feeble and helpless state, it might be supposed, we re- 

 peat, that at this particular time it would be found, that trout 

 fed upon these young salmon. Now this most assuredly is not 

 the case. . About three dozen trout were taken on each of those 

 days, and all opened purposely to ascertain the fact, but their 

 stomachs were uniformly found full of aquatic insects, and in no 

 instance could the slightest remains of the salmon-fry be detected 

 as the food of the trout. It is needless to remark, that trouts of 

 various sizes were opened, lest it might be peculiar to trout of a 

 certain size to attack the fry in that condition. 



On the 20th April 1832, these rivers were fished with fly, 

 and were found full of salmon-smolts, varying from six to nine 

 inches ; such being the rapidity of their growth, from the 1st 

 to the 20th April, or in about three weeks. They were in the 

 finest possible condition, covered with small silvery scales, differ- 

 ing in shape (I mean the scales) from those of the trout or par. 

 They frequent the still water towards the foot of pools, and feed 

 exclusively on flies, cod-bait, and aquatic insects, during the whole 

 period of their residence in fresh water, their food differing in 

 nothing from that of the common trout. 



It is almost unnecessary, I hope, to remark, that the stomachs 

 of the fry were examined with great care by myself, and their 

 contents minutely inspected. They have not been observed by 



