Dear Darwin

Just a few last words, before I commit my vaporings to the public.¹

Of all the followers of Latreille in the mutability of species did any one of them use this in explanation of representative species in very distant localities?² See end  Von Baer, as you point out, was convinced by the facts of Geog. distribution that all Species were descended from one parent form, & I suppose must have been led to this by the phenomena of representation— Can you tell me if this was so? I have no time to consult the Zoog. & Anthrop. Untersuch.ⁿ.³

I find that Dana was the first (of all I have yet found,) who broached the doctrine of permanence of position of existing continents.⁴ You somewhere do the same for existing Oceans, & I read it lately, but for the life of me cannot turn the passage up. Also in the origin you imply this.⁵ But I do not know of any one except Wallace who has summed up all the arguments for it; & marshalled them with convincing force⁶

I know Blytt’s paper & had it, & thought at the time very highly of it, & my opinion is strengthened by reperusal. I give a sketch of it as the last advance towards a knowledge of the laws of Geograph. Distribⁿ..⁷ I shall return your copy soon with thanks.

Ever yrs | J D Hooker.

P.S. What I want to know if any one ever suggested that the representation for an instance of an Azorean plant by a Canarian was due to their having a common parent the offspring of which diverged generally from the parent type but converged in those localities, either through both varying in the same direction or by one varying in the direction of the other.