My dear old Backy

I am very sorry you have been again “slack”. Your 2 last letters very interesting & valuable, & you have got a fine lot of knowledge out of Sachs. But you are an impudent dog, as the beginning of your last note shows.—²

I sh^d. be very glad to see De Vries here, but we leave home on the 7^th. & shall be away about 3 weeks; though if Fanny Hensleigh sh^d. come here soon, we may, I suppose have to alter our plans. about returning.— Tell Vries this if you see him.³

Observe, if you can, whether the water obtains anything from the bloomless or cleaned petals of Helvingia.⁴ If you have any flowers, you might hang up a few cleaned & uncleaned about relative shrivelling or drying.—

Sachs remark about the stomata seems very important; yet I can hardly understand how with M. Mer the leaves of so many plants kept alive for many days or even weeks when fairly immersed in water. I thought that each leaf chiefly depended on its own power of breathing & nourishing itself. I wonder what Sachs w^d. say to Mer’s statements.—⁵

I quite agree with what Sachs says that certain actions of plants or effects on them are neither advantageous or disadvantageous: unless, for instance, light produced some tendency to move or some effect, there could have been no beginning to acquiring perfect heliotropism or apheliotropism.—⁶

My Porliera was last watered on July 6^th & yesterday it seemed dying; but the leaves have never slept during the day, even not those on twig in bottle with quick-lime. It did not even sleep last night from “dry rigidity”, but recovered when watered with wonderful quickness.— My notion now is that agitation from wind & dryness is cause of the diurnal sleep.—⁷

Your affect Father | C. Darwin

Your observations on manner of growth of free & coiled twiners seems eminently well worth investigation.—⁸

I wrote on double paper by mistake⁹