SALMON. 31 



window along a wooden channel fitted up for the purpose. 

 As there was no fire in the bed-room, and the window facing 

 the north, the temperature did not range very high, 47 

 being the average, while the average temperature of the water 

 in the tumbler was 45. During the night, however, the 

 temperature would be very considerably increased, and the 

 consequence was, the young fish in the tumbler were hatched 

 in thirty-six hours, while those remaining in the stream did 

 not hatch till the 28th of April, a difference of nearly seven 

 days. At this stage the little fish are so very transparent, 

 that their vital organs are distinctly visible, and, when placed 

 immediately under the eye of the observer, they present a 

 very interesting appearance. The pectoral fin is continually 

 in rapid motion, even when the fish itself is otherwise in a 

 state of perfect repose. They also begin to manifest an in- 

 creasing desire to escape observation, a principle wisely im- 

 planted for their better security, during so feeble and helpless 

 a condition. On the 24th of May (thirty-nine days after 

 their birth), the fish in the tumbler were completely divested 

 of the yolk, and the characteristic bars of the Parr had be- 

 come visible. At this time they measured nearly one inch 

 in length, and appeared to be in perfect health ; but fearing 

 that after the yolk was consumed, I should be unable to 

 supply them with appropriate food, I returned them to the 

 pond from which I had taken them on the 20th of April, 

 where they perished with the rest of the family. 



" This last experiment proves, that by placing the ova 

 under a temporary stream of water in the house, the develop- 

 ment of the young may be materially accelerated, while it 

 also shows that they may be kept alive for a considerable 

 time afterwards ; at all events, until the yolk, which I pre- 

 sume to be their sole support at this period, is totally con- 

 sumed. 



" The next experiment, the circumstances of which I have 



