22 THE ACCLIMATISATION 



the responsibility to Mr. Youl, which he 

 accepted on condition that he should have 

 supreme authority. 



Convinced that there was yet much ta 

 learn, Mr. Youl set about a series of experi- 

 ments designed to test the vitality of salmon 

 ova at a low temperature, and for this- 

 purpose the Wenham Lake Ice Company 

 allowed space in one of their vaults. It is; 

 important to give the details of this, because 

 it elicited three heretofore unknown facts — 

 first, that a continuous and full stream of 

 water is not essential to the preservation of 

 vitality ; second, that partial deprivation 

 of air is not fatal ; third, that light is not 

 necessary. On the 17th of January, 1863, 

 5000 salmon ova were obtained from a female 

 and fertiUsed by the milt of one male. From 

 200 to 600 ova were placed in each of eleven 

 wooden boxes, filled with moss taken from 

 one locality and distributed carefally among- 

 it. Seven of these were covered with blocks 

 of ice some 2 ft. thick, and the whole buried 

 under 2 ft. of sawdust. Few believed that 

 a single ovum would be found alive at 



