82 MR. HOGG ON THE MODES OF 



said to have been * perforated ;' thus, then, some of the milt might 

 have readily been carried with the stream through the holes into 

 the zinc box, and so have fecundated the roe, or ova, deposited 

 within it. The fry would then, in the course of nature, be 

 brought to life. 



" But I may observe, that * Ephemera,^ or Mr. Fitzgibbon, 

 seems to differ from the view which I have taken of the possi- 

 bility of my first solution, which is deduced from Mr. Ellis's 

 description of the male and female salmon ' rubbing against each 

 other,' when spawning, as he mentions ' the improbability of 

 impregnation by intromission or coitus, either before, or at the 

 time of the deposition of the ova.' (See ' The Book of the Sal- 

 mon,' by Ejpliemera and Mr. A. Young. P. 186. Lond., 1850,) 

 He does not, however, state the impossibility of this process. It 

 may indeed take place, though perhaps very rarely. Nature, we 

 know, has given to the male semen of all animals a vivifying 

 influence (^spermatozoa) of great effect; insomuch so, that not un- 

 frequently, a very minute portion* is sufficient to fecundate the 

 ova of the female. Hence, then, to say that the roe of female 

 fish will produce fry, or the young, without having received any 

 influence whatsoever from the milt of the males, is monstrous, 

 and altogether a different subject, which Dr. Robertson, in the 

 account I have just read, does not assert." 



Next, in order to show how far the above paper, or at least the 

 principal part of it, may have become generally known, it will 

 be necessary to insert here portions of the abstracts of the same, 

 according to their respective dates of appearance. 



Tho, first of these was briefly given in the " Literary Gazette" 

 of June 18, 1853, which states at p. G03, as follows: — "Mr. 

 Fisher finished his letter with some observations on what he 

 considered an incorrect statement in a newspaper, concerning a 

 Dr. Robertson, in Scotland, having ' taken some roe from a female 

 Salmon (Trout J. H.) without milting it, and that it had pro- 

 duced the fry.' Mr. J. Hogg read the account itself, as pub- 



* " Mr. Shaw, in his memoir, published in the 'Trans, Royal Society of Edinbro',' 

 writes, ' that the milt of a single male P«rr, whose entire weight niaj' not exceed one- 

 and-a-half ounce, is capable, when confined in a small stream, of effectually impregnat- 

 ing all the ova of a very large female SaLwon.^ " 



