4992 Fishes. 



salmon from a parr, or, as I would call it, a generic jish, to a smolt might 

 be prolonged for a year at least ; some experiments made on the Dee, 

 near Kircudbright, extended the retardation of the development to 

 another year, and so on ; or, in other words, the young of the salmon 

 might, under certain circumstances, continue to hold their generic 

 characters for an indefinite period, instead of assuming their last 

 metamorphosis. There was nothing novel in such experiments, 

 the same having been proved to happen in the development of 

 the Batrachia. But that which is curious, and which still requires 

 explanation, is, that numerous — I had almost said innumerable — 

 small fishes, obviously affiliated, if not directly sprung from, the 

 salmon, continue to occupy salmon rivers throughout the year, 

 whilst thousands and thousands, not larger, and many smaller, have 

 undergone their last metamorphosis and migrated to the unknown 

 recesses of the ocean. Of those which migrate in May, I have never 

 observed the roe or the milt to be in the slightest degree altered, or 

 even to look as if it had ever undergone a change ; whilst, in the du- 

 bious fish remaining in the river, the milt, as is well known, becomes 

 highly developed. Is it a law, then, that of the ova of a single incu- 

 bation a certain number become fully developed after a residence in 

 the fresh waters of a few weeks ; a certain number at the end of a 

 year ; a still greater number never, but, retaining their generic dress, 

 continue in this dwarfish state in the fresh-water rivers ? These are 

 the appearances the question assumes at present, to solve or explain 

 which both methods will no doubt be required, that, namely, by direct 

 observation and that by experiment. 



Economically : salmon are gregarious wild animals, submitting to 

 no restraint; their abundance or scarcity depend on circumstances 

 over which man has little or no control ; but as they breed in confined 

 streams, the inhabitants of all civilized countries will succeed, as is 

 their wont and nature, in destroying them, by attacking the spawning 

 fish and her brood. This is in accordance with man's seeming mission 

 on earth — that of a destroyer of Nature's works : in Southern Africa 

 you can predict the proximity of civilized man by the wilderness 

 which moves before him, in advance, marking his all-destroying 

 character. 



R. Knox. 



Meissen House, Upper Clapton, 

 December, 1855. 





