' SPREAD OF SPECIES. 167 



f reason to believe, through the instrumentality 

 of ice, I think you will allow that this idea 

 of the mode of distribution comes within the 

 scope of probability. 



AMICUS. What you say seems plausible ; but 

 is there not a more commonly received notion 

 as to the manner of the spread of species, at 

 least, of certain species, those in greatest es- 

 timation, viz., by artificial means rather than 

 by natural? When speaking of the grayling, 

 you mentioned the conjecture that it was 

 introduced into this country in the time of the 

 monastic institutions, and I think I have read 

 in one of your provincial papers, that the charr 

 of the Lake District was similarly imported. 



PISCATOK. It is a popular notion that the 

 monks were our great benefactors in this re- 

 spect. It is a most easy way of explaining the 

 fact the spread of certain fish ; and how can 

 we gainsay it or prove a negative ? That in 

 some instances they may have introduced 

 certain fish is highly probable; but it does 

 not thence follow that natural causes have not 

 been in operation, effecting the same thing. 

 And, if we enter fully and fairly into the sub- 

 ject, I think we must arrive at the conclusion 



M 4 



