From James Niven to Francis Darwin   12 March 1882

Dear Sir

In reading your father’s wonderful book on Worms, I was very much struck with the account of the intelligence shown by worms. You will remember the part where the worms block their burrows with double spines of fir, dragging them in by the part where the two leaves join and persist in doing so after the tips have been fastened together.¹

In the species most common about here the spines are rough on one side when rubbed from tip to the junction of the two, comparatively smooth when rubbed from the junction to the tip. Whether this is so generally or not I dont know, but with these spines the tactile sensibility of worms; and their experience in locomotion might determine the choice to some extent. This is scarcely worth mentioning and I have little doubt it has been noticed and considered insufficient. However I thought that on the new principle of de minimis lex curat² I sh^d mention it to you

Yours truly | J. Niven