498 Dr KNOX on the Natural History of 



anatomy as a science formed the sole object of my pursuits, to remedy if possible 

 these omissions, I have taken every opportunity to investigate the various questions 

 on the spot, by repairing, when practicable, to the salmon-rivers, exploring them from 

 their sources to their conflux with the sea ; by looking into every thing myself, and 

 as seldom as possible trusting the fishings of these rivers to others. Notwithstanding 

 these efforts, which were attended with a good deal of inconvenience, particularly in 

 the examining the state of the rivers at a distance from town, it cannot but be that 

 many errors must have crept into these memoirs. As the whole question is with me 

 strictly a scientific one, and being no further interested in the numerous difficult pro- 

 blems it embraces, than as regards the investigation of truth upon a physiological ques- 

 tion, the memoir will be found not so much extended on some practical points as per- 

 haps the public desired. 



APPENDIX B. 



Evidence and Report to the House of Commons on the Salmon Fisheries of t/ie British 



and Irish Rivers. 



It is in evidence on the part of Sir H. DAVY, that he considers six weeks sufficient 

 for the development of the salmon ova, i. e. from the period of its deposition until its 

 appearance in the stream as a fish. This would bring the smolts into the stream at a 

 time when there was no food for them. Moreover, the opinion is refuted by the most 

 positive intuitive evidence. Every science must have a basis. Now, the question of the 

 generation of animals is the most obscure and difficult of all questions in physiology, 

 a science resting entirely for its basis on anatomy. Sir H. DAVY being unacquainted 

 with these sciences *, was not competent to make observations on the mode of genera- 

 tion of the salmon. 



In a succeeding passage of the paper I now remark on, the editor observes, that " in 

 August and September, a fish exactly resembling the young salmon in form, and from 

 ten to fourteen inches long (called Whitlings and Whitings), without visible ova or 

 spermatic secretion, are found in salmon rivers, a mile or two from the sea, and which 

 return to the sea without attempting a further migration." P. 145. 



To what species of fish Sir H. refers, in the passage above quoted, I cannot imagine. 

 Does he mean that in the young salmon, fourteen inches long, the sex of the fish cannot 

 be determined, and that the ovaria and milt are not to be seen ? Personal repeated 

 observation has shewn me, that in the salmon smolt, whilst yet at the sources of the 

 rivers, and only six inches in length, and previous, of course, to their descent to the 

 sea, the sexes can be distinguished from each other with the greatest ease, the organ 

 of generation being already partly developed. It is by no means difficult to distinguish 

 the sexes in smolts, even without the aid of anatomy, since the lower jaw of the male 

 (as in the trout) is stronger than in the female, and already displays that process pro- 



I take this position as proved by a passage in the Salmonia, where Sir H. DAVY speaks of the 

 whale having no swimming-bladder. 



