MR. SHAWS EXPERIMENTS 29 



the most interesting, and which has been lately 

 received by the Royal Society of Edinburgh, 

 contains a continuance and confirmation of the 

 results of the experiments mentioned in the two 

 first papers above alluded to, together with the very 

 extraordinary fact, that the milt of a parr eighteen 

 months old, and only weighing an ounce and a half, 

 is capable of impregnating the ova of a full-grown 

 salmon. 



Before proceeding to make the experiments 

 related in his last communication, he made three 

 ponds, the banks so raised, and constructed other- 

 wise in such a manner, that it was impossible for 

 the young fish to escape, or for any other fish to 

 have access to them. Accurate drawings and 

 descriptions of these ponds are given in his printed 

 pages, now before me, which he was so obliging as 

 to present me with. " Being thus prepared," says 

 Mr. Shaw (alluding to the construction of his 

 ponds), "with every means of carrying my ex- 

 periments into practice, I proceeded to the river 

 Nith on the 4th of January, 1837, and readily 

 discovered a pair of adult salmon engaged in 

 depositing their spawn. They were in a situation 

 easily accessible, the water being of such a depth as 

 to admit of my net being employed with certain 

 success." The fish were accordingly captured by 

 means of a hoop net. The ova were then pressed 

 with the hand from the body of the female, and 

 impregnated in the same manner by the milt of the 

 male, and the spawn in this state was transferred to 

 a private pond previously prepared for its reception. 

 That there might be no doubt as to the species, the 



