Fishes. 4709 



On the Food of certain Gregarious Fishes. 

 By R. Knox, M.D., F.R.S.E., &c* 



At an early period of my inquiries into the natural history of the 

 Salmonidae, I was much struck with the difficulty there seemed to be 

 of arriving at the truth in a matter so simple in appearance as the 

 determination of the food on which certain interesting gregarious fishes 

 live and thrive. The conflict of opinions on this point which then 

 existed, and strange to say still exists, induced me to devote a good deal 

 of attention to it ; and as I find my views still opposed to many, and 

 especially to those of my esteemed and distinguished friend M. 

 Valenciennes, I have thought it might serve the cause of science and 

 of truth to submit a memoir on the subject to a society, venerable as 

 well by its name as by the services it has rendered the sciences of 

 observation. 



The inquiries, of which the results are merely given here, were 

 commenced about 1824, or about thirty years ago; and although I 

 have repeated them on many occasions, I do not find it necessary to 

 alter or modify the statements originally made on this point to the 

 Royal Society of Edinburgh, in whose ' Transactions' a mere notice 

 of my researches and observations were published. 



My attention was first directed to the fact, for such it is beyond a 

 doubt, that in the stomachs and intestines of fresh-run salmon, that 

 is, of salmon fresh from their best, indeed their only true feeding- 

 ground, the unknown recesses of the ocean, nothing is ever found 

 but a peculiar reddish substance (and that in small quantity), unlike 

 anything known to possess life. The reddish coloured matter is also 

 found in the intestine. On applying to practical fishermen, that is, to 

 those who had seen, I shall not say examined, hundreds of salmon 

 opened and gutted, I found that they had but one opinion on the 

 subject, namely, that the food of the salmon, whilst a resident in the 

 ocean, was altogether unknown. 



On inquiring of the same class of persons as to their knowledge of 

 the food of the herring, I found them equally at fault. They spoke 

 vaguely about the herring living by suction, but they were agreed as 

 to the main fact, namely, that food discernible to the naked eye w r as 

 rarely to be found in the stomach of the herring. Whilst reflecting on 



* Read December 19th, 1854, to the Linnean Society. Communicated to the 

 Linnean Society by William Yarrell, Esq., V.P.L.S. 



XIII. 2 A 



