My dear Dyer

I am heartily obliged for the plants & seeds which arrived safely & several of them will be of extreme use to me.—²

I hope that you will give from me my thanks to M^r. Lynch.—³

With respect to the tiny plants of Melocactus they are much too old; what I require to see is the plumule or cotyledons (as the case may be) as or before they break through the ground.⁴ I have therefore been thinking that it w^d be the best plan for us to attempt again raising seeds of some Cacteæ, for I forgot that the pots require for my purpose to be daily examined. Will you therefore ask M^r Lynch to let me have any seed or fruit, which he can get of any Cacteæ (avoiding Opuntia nigricans & Rhipsalis cassytha, which so disgracefully failed with us);⁵ asking him moreover to mark on packet what temperature & kind of soil they ought to be sown in.—

From same cause it w^d be better to send me a few seeds of Pachira with instructions about sowing.⁶ This in the long run w^d. give less trouble than raising seedlings for me.—

I was very much interested with your last letter about protoplasm, &c, about which I have sometimes thought though knowing very little.⁷ As the cell-walls grow I do not see why light, gravity contact &c—sh^d. not act on them directly, instead of through the protoplasm.— When examining Drosera, I took the impression that the cell-walls were undervalued.⁸

It is a frightfully difficult subject, & I shall avoid it, keeping to facts as much as possible.—

We are very sorry to hear not a very good account of M^rs. Dyer: some time ago we heard a very prosperous account.—⁹

Yours very sincerely | Ch. Darwin