50 SPECIES OF THE SALMON. 



being wrong, that I would take nothing for granted. 

 An universal zoology is more than any man can 

 accomplish of his own knowledge, and three parts 

 of what is published are taken from the reports 

 and the credit of others. 



It is not easy to ascertain, either the sincerity or 

 the correctness of an opinion. It may be extend- 

 ing this article, perhaps, further than is necessary, 

 but whilst we are upon the subject, a page or two 

 more may be pardoned. By analogy to other ani- 

 mals, we may see how ill- calculated external appear- 

 ances alone are, without referring to other circum- 

 stances, to distinguish one species from another. In 

 birds in particular this is the case, where the cocks 

 and hens vary so much in plumage, that were they 

 not reared from the same nest, and had we no other 

 positive evidence, no man living would believe that 

 they were of one and the same sort ; but simple 

 experiments in this way, prove the fact beyond 

 a doubt. It is by experiment, that we know the 

 cock and hen sparrow-hawk, the cock and hen 

 kestrel, varying so much in size and plumage, and 

 a great variety of other kinds, both wild and do- 

 mestic, which it might be deemed pedantry to men- 

 tion in this place, to be the same species. Every 

 writer treats the ringtail, and the white falcon as two 

 species (what we call the hen-harrier or furze kite), 

 but from nestlings I know them to be one species. 

 I shall stop short in the investigation of this very 

 favourite subject, my fondness for which might 

 carry me into an unreasonable length, by conclud- 



