DR DAVY ON THE SALMONID.E. 251 



young charr was put into a platina capsule about If inch across its brim, with just 

 sufficient water to cover it. It remained active fifty-two hours ; and it may have 

 been active longer, as it was found dead in the morning, the night hours not being 

 included in the time specified. In the second experiment, the young fish simi- 

 larly treated lived rather more than seventy-four hours. The capsule, it may be 

 mentioned, was covered with a slide of glass, to prevent rapid evaporation, and 

 yet not exclude air. In the third experiment, the young salmon was put into a 

 small liquor-glass, with a little water, little more than sufficed to cover it and 

 enable it to move freely, in weight no more than 47 grains. Left till the 22d ; 

 during these nine days it did not appear to have suffered from being so limited 

 and confined. Returned on this day to the vessel from which it had been taken, 

 it seemed unimpaired in vigour and activity. The temperature of the water, 

 in each instance, did not exceed 52° Fahr., and was never below 48°. 



These experiments, I need hardly point out, were made with the intent of 

 testing the power of endurance of young fish during periods of drought, when 

 they are liable, from the lowering of the streams, to be left almost dry. 



The result of the last experiment, I may remark, was somewhat different from 

 what I had expected, supposing, as I previously did, that the air necessary for 

 supporting life would soon be exhausted in so small a quantity of water ; not 

 taking into account that the motion of the fish (and it was very restless) might 

 promote the absorption of air ; and that even the small volume of water so fully 

 exposed, and almost constantly agitated, would conduce to the same. 



6. Of the Food of the Young Fish. 



In consequence of the attention that is now being paid to the artificial pro- 

 cess, as it has been called, of breeding fish, the question, what kind of food is 

 most suitable to the young fish when it has to provide for itself, after the con- 

 sumption of the store laid up in the vitelline sack, becomes one of considerable 

 interest. 



My own experience as regards the attempt to feed the young fish, is very 

 limited. The first trial I made was with finely-grated boiled beef; the second 

 with dried charr — the muscular part dried rapidly and pounded very finely. A 

 small portion of each Avas given daily to a different brood. The young fish fed 

 on the particles greedily, seizing them chiefly when in motion. Those which had 

 the charr seemed to thrive somewhat better than those fed on beef ; more of the 

 former attaining their perfect shape, as denoted by the development of the fins, 

 than of the latter. In a third trial no food was given. This was in the instance 

 of the brood hatched in the larger vessel, the earthenware pan, in which was a 

 considerable quantity of gravel and small stones, with the addition of some aqua- 

 tic plants from the river Brathay, - that part of it which is one of the breeding- 



