RESPECTING THE PARR. 43 



I received a very obliging answer from that gentle- 

 man, the purport of which was to say, that as his bill 

 had failed, it was not necessary to trouble me any 

 farther on the subject. 



This letter contains evidence that Sir David Brew- 

 ster's experiments were made previously to its being 

 written ; and when I had thought of publishing, being- 

 desirous to know the exact time when they w T ere made, 

 I wrote to Sir David to call his attention to the subject. 

 His answer, dated 16th of April, 1840, was as follows: 



" I am pretty sure that my experiments on the struc- 

 ture of the crystalline lens of the Parr, which is iden- 

 tical with that of the Salmon, were made previous to 

 1828.* I remember well your stating to me that when 

 the silver scales of the young Salmon (which in Rox- 

 burghshire we call Smouts) were carefully rubbed off, 

 the colours of a darker hue which characterise the Parr 

 w r ere invariably and distinctly seen. I think you 

 showed me the experiments, but I am not sure of this. 

 With the view of confirming this your theory, or of 

 overturning it, I mentioned to you that the fibres of 

 the lens of the salmon," etc. 



Then follows the account of his experiments, as de- 

 tailed a little farther on. 



Besides the reasons mentioned in the above letter, 

 there were other causes which influenced me in the 

 opinion I had formed; the two principal of which were — 



* The date of Mr. Kennedy's Bill, which 1 have but just ascer- 

 tain*!, proves that they were made in or before the year 1S25 ; 

 whereas Mr. Shaw's first account of his interesting experiments 

 appeared in the "New Edinburgh and Philosophical Journal" for 

 183G, vol. xxi. p. 99— eleven years after. 



