My dear Frank

I have not written before, because you said you wanted to forget Science, & I had nothing else to tell you.— I will now report progress.— I have read about 80 pages of Wiesner.¹ It is an excellent book, but he vivisects me in the most gracious terms, but most effectively.— I wish that the confounded book had never been published.— I think that he proves (by the way he found most of our facts true, but my explanations wrong) that the transmission of heliotropism to the lower part of the stem is a mistake. He maintains that the weight of the upper part, which bends first, compresses one side & stretches the opposite side & this leads to growth of the same kind as heliotropic growth.² I think it can hardly be the weight, but that the tensions are transmitted. He gives a beautiful experiment to prove the above.³ By Jove, I felt like Charles Lamb, when he hissed his own play.—⁴

His animus is against Light acting as a “reiz” or stimulus; but I am not yet inclined to give this up.⁵ He says my experiment with the seedlings at different distances from the lamp, not bending at all proportionally to the amount of light received, can be easily explained on physical laws; but unfortunately I cannot translate.⁶ The worst of all is (though I have not yet come to that of the book) that he strenuously denies that all growing parts circumnutate. I shall be anxious if he names the plants for you to test them under the microscope with your new dodge.—⁷ Confound the book, but there never was a more gracious controversialist.—

I have gone on trying about aggregation of chlorophyll; but no more evidence, except in Dionæa, in which it takes place in a very conspicuous manner.—⁸ I have wasted much time over this, but my time is worth nothing.

I have now begun again on roots of Euphorbia.⁹ By the way I am much pleased by my recent success in cutting sections, which success depends on my placing one finger on the razor & pressing it down while I slice.

I have had a letter this morning from F. Müller with a most extraordinary case of Crotolaria (Leguminosæ) the leaves of which sleep in an endlessly diversified manner, so that no two leaves on a young plant occupy the same position.¹⁰ This depends chiefly on all of those that can see the setting sun turning their faces to it & retaining this position all night. He is going to publish an account of this plant in Kosmos.¹¹

Good Bye dear old fellow. I hope that you will get well rested. We start on Thursday for Cambridge.¹²

Your affect Father | C. Darwin

Leonard comes to night to settle & pay for the Land & arrange with Laslett about the wall.¹³ Fanny Hensleigh & her maids are astonished at Bernard’s goodness.¹⁴