Some apparatus is coming from Cambridge to enable me to test for electrotonus and Pflüger's law. I shall apply it to the luminous Medusæ also, whose light, I forgot to say, is seen under the microscope in the dark to proceed not only from the margin alone, but from that particular part of the margin where Agassiz describes his chain of nervous cells.
Geo. J. Romanes.
From C. Darwin to G. J. Romanes.
Down, Beckenham, Kent: July 18, 1875.
I have been much interested by your letter, and am truly delighted at the prospect of success. Such energy as yours is almost sure to command victory. The world will be much more influenced by experiments on animals than on plants. But in any case I think a large number of successful results will be necessary to convince physiologists. It is rash to be sanguine, but it will be splendid if you succeed. My object in writing has been to say that it has only just occurred to me that I have not sent you a copy of my 'Insectivorous Plants;' if you would care to have a copy, and do not possess one, send me a postcard, and one shall be sent. If I do not hear, I shall understand.
Yours very sincerely,
Ch. Darwin.
Dunskaith, Nigg P.O., Ross-shire, N.B.: July 20, 1875.
My dear Mr. Darwin,—Your letter arrived just in time to prevent my sending an order to my bookseller for 'Insectivorous Plants,' for, of course, it is needless to say that I shall highly value a copy from yourself. At first I intended to wait until I should have more time to enjoy the work, but a passage in this week's 'Nature' determined me to get a copy at once. This passage was one about reflex action, and I am very anxious to see what you say about this, because in a paper I have prepared for the 'B.A.' on Medusæ I have had occasion to insist upon the occurrence of reflex action in the case of these, notwithstanding the absence of any distinguishable system of afferent and efferent nerves. But as physiologists have been so long accustomed to associate the phenomena of reflex action with some such distinguishable system, I was afraid that they might think me rather audacious in propounding the doctrine, that there is such a thing as reflex action without well-defined structural channels for it to occur in. But if you have found something of the same sort in plants, of course I shall be very glad to have your authority to quote. And I think it follows deductively from the general theory of evolution, that reflex action ought to be present before the lines in which it flows are sufficiently differentiated to become distinguishable as nerves.