To Andrew Murray 28 [April 1860]1
Down Bromley Kent
My dear Sir I omitted one little criticism on your explanation of the use of
Hybridisation on the supposition (singular enough as it seems to me) of all the males of a rare species dying.2 Do you not think that you ought to say that this applies only to the unisexual animals & to but few plants—unless indeed you choose to suppose the male organs to fail in acting, during same season in all the individuals of a species. Such astonishing precautions to prevent extinction, seeing that the extinction of every form of life in the course of time is a law of nature, seems to me rather improbable.—
I rather suspect that Owen & many of my other reviewers would have hit me hard had I advanced a view of this nature without facts in support.—3 Forgive me for troubling you; for I well know that you wish to make your Review as true, as well as as just, as possible.—
My dear Sir | Yours very sincerely | C. Darwin
P.S. Forgive me for adding one word. I rather dispute that Oken, Lamarck & Co. throw some light on Classification, Embryology & Rudimentary organs &c.—, as the theory of Nat. Selection seems to me to do.—4 In the case of Embryology there must be introduced the principle of variations not supervening at very early age & being inherited at corresponding age.— So with Rudimentary organs combined with disuse & Nat. Selection.—
In case of classification, descent alone, as I believe I have shown, will not do; you must combine principle of divergence of character & descent from dominant & increasing forms.— But as you do not believe in my notions it is folly in me pointing out how they differ from the notions of my predecessors—
In his former note CD omitted to criticise AM’s explanation that the function of hybridisation is to prevent extinction should the males of a rare species die out.
Disputes that "Oken, Lamarck & Co throw some light on Classification, Embryology & Rudimentary organs". In the case of embryology there must be introduced the principle of variations not supervening at a very early age and being inherited at corresponding ages. In classification descent alone will not do; it must be combined with the principle of divergence of character and descent from dominant and increasing forms.