SPECIES OF THE SALMON. 49 



transformation, could any one believe, that the cater- 

 pillar, the aurelia, and the butterfly were one crea- 

 ture ? All the opinions of naturalists which I have 

 seen, rest wholly on observation on external 

 marks, and some other trivial distinctions, than 

 which nothing can be more fallacious throughout 

 nature, particularly between the male and the fe- 

 male of birds and of fish. They give no other 

 reasons — no kind of proof by experiment — no 

 positive fact, or any series of reasoning, or compa- 

 rison of analogy, by which we can come to a satis- 

 factory and decisive conclusion that the fish are 

 different. Opinions which are not formed of 

 sound and solid materials, fact and reason, are 

 like a vapour, they carry conviction not beyond 

 " the whistling of a name." A truth proved by 

 such experiments as those of my Carlisle corres- 

 pondent, is worth all the loose and hasty opinions 

 and assertions of all the naturalists in the universe. 



" Pride often guides the author's pen, 

 Books as affected are as men." 



To find out truths, we must go to facts and ex- 

 periments. Recollect what that sublime writer, 

 BufFon, says of the change of an ox's horns, con- 

 tinued through three editions of his " Natural His- 

 tory." Let it prove to us, that we should be 

 cautious how we repose implicit confidence in the 

 dicta of any man. Facts, then, are of much more 

 consequence than the names of authors. I have 

 seen and know so many instances of naturalists 



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