My dear Romanes

As I feared, I cannot be of the least use to you. I couldn’t venture to say anything about babies without reading my expression book, & paper on infants; or about animals without reading the Descent of man & referring to my notes; & it is a great wrench to my mind to change from one subject to another.¹

I will however hazard one or two remarks. Firstly I should have thought that the word ‘love’ (not sexual passion) as shown very low in scale to offspring & apparently to comrades, ought to have come in more prominently in your table than appears to be the case.²

Secondly if you give any instance of the appreciation of different stimulants by plants, there is a much better case than that given by you. Namely that of the glands of Drosera which can be touched roughly 2 or 3 times & do not transmit any effect, but do so if pressed by a weight of $\frac{1}{\mathrm{78,000}}$ grain (Insectiv Plants 263). On the other hand the filament of Dionæa may be quietly loaded with a much greater weight with no effect, while a touch by a hair causes the lobes to close instantly.³ This has always seemed to me a marvellous fact.

Thirdly I have been accustomed to look at the coming in of the sense of pleasure & pain as one of the most important steps in the development of mind; & I should think ought to be prominent in your table.⁴ The sort of progress which I have imagined is that a stimulus produced some effect at the point affected; & that the effect radiated at first in all directions, & then that certain definite advantageous, lines of transmission were acquired, inducing definite reaction in certain lines. Such transmission afterwards became associated in some unknown way with pleasure or pain. These sensations led at first to all sorts of violent action such as the wriggling of a worm, which was of some use. All the organs of sense would be at the same time excited. Afterwards definite lines of action would be found to be the most useful & would be practiced. But it is of no use my giving you my crude notions

Yours very sincerely | Ch. Darwin

The diagram is returned as may wish to show it some one else