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—