The Fungus of Salmon Disease. 8 1 



years in the rivers, may have resulted in gradual degeneration 

 of the fish in some important point of their strength or vitality. 

 This latter opinion is not a new one, and is obviously the first 

 that would suggest itself to any impartial mind with some know- 

 ledge of the subject. 



The fungus appears to be exercising its instinctive mission, 

 thriving and living freely, while enjoying unusual oppor- 

 tunities. It seems almost to take possession of a river, and the 

 fish are unable to resist its attacks. There is nothing mys- 

 terious, so far as the fungus is concerned, in the manner in 

 which this is brought about. We probably know as much as is 

 necessary about the fungus, and any points in its history that 

 remain unstudied could be worked out with exactitude to the 

 smallest detail with time and patience. Can the same be said 

 for the salmon ? I believe not ; and I venture to think that it is 

 the missing link in their history which requires all the energy of 

 investigation to elucidate this subject. If the disease should 

 eventually die out and leave our rivers improved rather than 

 otherwise, the theory will be forced on us that it is due to the 

 succession of an improved and more vigorous race of fish having 

 succeeded the ones that succumbed to the disease earlier ; but 

 we shall have learned that the epidemic may again appear if 

 degeneration to the same extent should give it another oppor- 

 tunity of flourishing ; and the lesson will probably cause to be 

 introduced many necessary measures now imperfectly under- 

 stood, or disregarded as of but trivial importance. 



One apparently astonishing fact has been revealed by the 

 Fishery Inspectors' statistics, as we learn that in some of the 

 rivers where the disease has been most virulent the value of 

 fishing (calculated from the number of salmon taken) has greatly 

 increased, while in other rivers the class of fish are reported as 

 being much improved. Such facts would suggest that there 

 may be a hidden good even in salmon disease by its killing off 

 weakly fish, or pointing out defects or changes, that may have 

 gradually arisen to interfere with their happy life history. 



