70 THE SALMON. 



to grow to become salmon, they apparently begin to 

 grow backwards ; as in October we have them as small 

 as we had them in May, not growing one inch larger 

 from that time till they return to the sea in March and 

 April as kelts. ... If grilse grew to be salmon, and as 

 rapidly as is generally supposed, we should have no grilse 

 in October, but all salmon." We have two accusations 

 against this passage : the ideas are confused, and the 

 allegations are unproved and improbable. In the first 

 place, there is a confusion between the individual arid 

 the species. Mr. Mackenzie speaks as if the grilse that 

 ascended in May were the same individual grilse that 

 ascends in the later months of the year, and asks why 

 the individual has not grown any in three months ; 

 whereas there are two different persons, of much about 

 the same age, in so far as they were born in the same 

 year, the difference in their periods of ascent arising 

 mainly from the slight difference of several weeks in 

 the date of their birth or of their descent, and from 

 the variety of circumstances that have shortened or 

 prolonged their residence in the sea, the late-comers 

 being for the most part those which have remained 

 longest, and consequently grown largest. In the second 

 place, Mr. Mackenzie has strangely assumed that it 

 is maintained that grilse grow into salmon whilst in 

 the fresh water ; whereas, what is maintained is, that 

 besides not growing in size in the river, grilse do not 

 even begin to grow into salmon until they return to the 

 sea ; that they ascend as grilses, descend as grilse-kelts, 

 and after their return to the sea become salmon, and as 

 such reappear in the rivers. Then, as to the facts, 



