THE EFFICIENT CAUSE 519 
loosely much written about, often broached and attempted, 
of transmutation by saltus ; Owen is hedging for it in his 
review of Darwin and snub of me in Edinburgh Review, 
and there is a deal to be said for it ; I have often carefully 
examined it for plants, this 15 years ; but have failed to find 
any reasonably cumulative support in facts, and none in 
Geog. distrib. or classification. Other views will turn up, 
but in the present state of science, I look to an advance on 
Darwin's general views as [the] most hopeful future. 
Ever yours affectionately, 
Jos. D. HOOKEK. 
Kcw : Tuesday, 1860. 
Dear Harvey, — I sent Darwin the note of your objec- 
tion to Nat. Selection as the efficient cause, that he might 
clearly see that I was not singular in my view that his words 
state far more than he means if taken in the serise you and 
others take them. He was anxious to write to you, and I told 
him I was sure you would be glad to hear, but not till after 
your Lectures. Do not be dragged into a discussion of the 
subject till you are at leisure. Thwaites has written an un- 
conditional surrender to Darwin's view under ^present aspect 
of question. 
Ever yours affectionately, 
Jos. D. Hooker. 
Dear Harvey, — I see you are going in for a transmuta- 
tion doctrine after all ! and evidently the one that Owen is 
hedging for in his review of Darwin (and snub of self) in 
Edinburgh Review. 
1 have enquired about Cowslips, etc., and will let you 
know. The battle will now be between transmutation by 
saltus and by slow measures. How you can deny N. S. in 
either case is to me incomprehensible ! Every real natura- 
list owns N. S. to be a vera causa, though few admit the 
plenary power that Darwin gives it. In our Herb, there is 
every intermediate between Primrose and Oxhp. 
You seem to confound variation with Nat. Selection. 
N. S. is not itself divarication ; it no more accounts for 
divarication than ' gravity ' accounts for the motion of 
planets. Give time, abate prejudice, and let your ideas 
clarify, which they will assuredly do in timp Bemember 
