INTRODUCTION. XXIX 



stream from the brook was then led into this hollow, so as to 

 form a pool of about eight inches in depth at the upper, and 

 three feet at the lower end : thus giving it one gentle uniform 

 current over the whole pool, whilst the supply of water was so 

 regulated by a sluice as to have the same depth at all times, 

 and a strong stone wall excluded all Eels or Trout, so de- 

 structive to both spawn and fry. 



" On the 13th of November, four pair of Salmon, male and 

 female, were taken by net from the Ewe, and carefully placed 

 in the pool. On the 18th they showed a disposition to 

 spawn, but on the 20th the whole were carried away by some 

 ill-disposed persons, and on examining the pool only a small 

 quantity of ova appeared to have been deposited. On No- 

 vember 23rd, four pair of Salmon were again caught, and placed 

 in the pool, which were observed to commence spawning on 

 the day following. Caught them carefully. Squeezed gently 

 about 1,200 ova from a female into a bason of water, and 

 then pressed about an equal quantity of milt from a male fish 

 over them. 



" Stirred the two about together gently, but well, with the 

 fingers, and after allowing them rest for an hour, the whole 

 was deposited and spread in one of the wicker baskets recom- 

 mended by Professor Agassiz, having above four inches of 

 gravel below and two or three inches of gravel above them. 



" A similar quantity of ova treated in the same way was 

 also deposited in one of the copper wire-bags, as used by Mr. 

 Shaw, and both were then immediately placed under water in 

 the pool. A little of the ova was buried in the open gravel 

 at about three inches in depth. In another basket, and also 

 in another copper wire-bag, two or three inches of gravel were 

 placed over the bottom of each, and both basket and bag laid 

 in the pool, covered with about four inches of water. The 

 ova of a female, and milt of a male, were then successively 

 squeezed from two fish on the gravel in both basket and bag, 



