1852.] Linnean Society. 179 



'Book of the Salmon.' They were taken from three female and 

 two male fishes on the night of the 27th of December, and not depo- 

 sited in the gravel of a small rivulet until the 29th of the same 

 month. Part of the ova were also placed in a gravel bed in the 

 river Swale ; but of the result of this part of the experiment Mr. 

 Fisher has no present information. In one part the ova were 

 placed too deep in the gravel, and on examination were found to be 

 addled ; while there is every reason to believe that those which were 

 placed about 3 inches in the gravel have all been hatched. A live 

 fish brought from the spawning-bed leaped out of the vessel in which 

 it was kept and speedily died, and the two mentioned in the pub- 

 lished letter also died in the course of about ten days, probably in 

 consequence of the disturbance to which they were exposed from the 

 curiosity of those who came to see them, and who were desirous of 

 observing the extreme velocity with which they moved round the 

 vessel, even while the vitelline bag was still attached to the abdo- 

 men. The spawning-bed was formed in a small run of spring- water 

 which is never affected by the frost ; it was cleared of minnows, 

 j^oung trout, &c., and at each end of a space of about twenty yards, 

 whins were placed of a good height, kept down with stones, to pre- 

 vent the entrance into it of other fish. After some observations re- 

 specting minnows, Mr. Fisher adds : " We have proved the fact that 

 the river Swale may be again stocked with salmon, provided we caa 

 make arrangements with the proprietor of a mill-wear, twenty-five 

 miles from this place, to let the fish, on coming up from the sea, 

 have ' free- gap ' from time to time." 



On these letters Mr. Hogg observes, that it seems to him there 

 can be little (if any) doubt that, with the precautions indicated, a 

 vast increase of salmon might be obtained, and a sure and valuable 

 source of wealth be secured in many suitable streams in which no 

 salmon are at present found ; and the same artificial process of 

 breeding might likewise be applied to trout with an equally advan- 

 tageous result. He suggests that the breeding might also be carried 

 on in large wooden boxes or cases, having a layer of gravel at the 

 bottom 4 or 5 inches deep, in which the ova and milt, or impreg- 

 nated ova, might be buried, and the cases filled with ])ure water, 

 which might be kept constantly fresh by allowing a small stream to 

 run into them. When the fry had grown sufficiently strong, they 

 might be conveyed to any distance in tubs filled with water, which 

 might be occasionally renewed, and having tops perforated with 

 holes. On the subject of the distribution of the species of fresh- 

 water fishes, Mr. Hogg refers to the presence of trout and other 



