My dear Sir

I was with M^r. Wood this morning, & he expressed himself strongly about your & your daughter’s kindness in aiding him.—² He much wants assistance on another point; & if you could aid him, you would greatly oblige me.—

You know well the appearance of a dog, when approaching another dog with hostile intentions, before they come close together. The dog walks very stiffly, with tail rigid & upright, hair on back erected, ears pointed & eyes directed forwards. When the dog attacks the other, down go the ears & the canines are uncovered. Now could you anyhow arrange so that one of your dogs could see a strange dog from a little distance, so that M^r Wood could sketch the former attitude, viz. of the stiff gesture with erected hair & erected ears.— And then he could afterwards sketch the same dog, when fondled by his master & wagging his tail with drooping ears. These two sketches I want much, & it would be a great favour to M^r Wood & myself, if you could aid him.³

My dear Sir | Yours very faithfully | Ch. Darwin

P.S When a horse is turned out into a field he trots with high elastic steps and carries his tail aloft. Even when a cow frisks about she throws up her tail. I have seen a drawing of an elephant, apparently trotting with high steps, & with the tail erect. When the elephants in the Garden are turned out and are excited so as to move quickly, do they carry their tails aloft? How is this with the rhinoceros? Do not trouble yourself to answer this, but I shall be in London in a couple of months & then perhaps you will be able to answer this trifling question.⁴ Or if you write about wolves & jackals turning round, you can tell me about the tails of elephants or of any other animals.—

C. Darwin