194 ON THE BREEDING OF SALMON. 



occur. Give it even the advantage of Mr. Halliday's 

 testimony before the House of Commons while de- 

 scribing the operation in question : " Salmon," says he, 

 "when spawning, work up the gravel and make their 

 furrows ; then parting, throw themselves on their sides, 

 and coming together, so shed their spawn" This mode 

 of procedure Mr. Shaw is evidently slow in admitting. 

 He passes it over in silence; yet admitted, it plainly 

 favours, if it does not entirely coincide with his manner 

 of experimenting (Transactions of R. S.,Edin., vol. xiv., 

 p. 554.) He says, " In conducting the experiment of 

 artificial impregnation, it appeared to me very desirable 

 that the male should be taken with the female of its own 

 selection, at the very moment when they were mutually 

 engaged in the continuance of their species. To take a 

 female from one part of the stream and a male from 

 another might not have given the same chance of a suc- 

 cessful issue to the experiment. Having drawn the fish 

 ashore, I placed the female, while still alive, in the 

 trench, and pressed from her body a quantity of the 

 ova. I then placed the male in the same situation, 

 pressing from his body a quantity of milt which passing- 

 down the stream thoroughly impregnated the ova," &c. 



Mr. S. evidently, in the instance detailed, acknow- 

 ledges as essential the existence of a mutual under- 

 standing betwixt the sexes. It is otherwise in his 

 experiments with the milt of the parr, which, he 

 contends, is as effective in impregnating the ova of 

 a full-grown solar as is the milt of its appropriate 

 mate. 



But to return to the matter under consideration, and 

 it is of no consequence whether Mr. Halli day's descrip- 

 tion of the manner in which the roe and milt are simul- 

 taneously expressed is correct or not, what, I ask, is 



