My dear Sir,

First of all I must beg your pardon that I write so very late to thank you for your kind and sympathizing letter, which reached Gersau when I had left already.¹ I had been hoping that I might get over the worst of our climate by coming back before October, so that some warm weeks might aid me in acclimatising. But I had the bad luck to travel just in those days when the temperature fell suddenly almost twelve degrees (C.). So I caught a new cold; on the whole, however, I feel much stronger and better. I had left Leipzig still with some daily feverish excitement and not quite recovered. This is all gone and I hope to be able again to work hard. I was not able to work in Gersaw; I read some proof sheets, that was all. I am here a fortnight, and yet I couldn’t find a spare hour to write letters. Herr Koch wishes the translation of your Expression to come out at the same time with the Original.² Now I have done about half of it and the printing has begun. I am delighted with the book; and if I venture to make some remarks on it, I trust you will not mistake the really great interest I take in it.

P. 41. you say: “the iris is not known to be under the conscious control of the will in any animal.” To make the statement correct you ought to say “in any mammal.” For the muscles of the Iris and the Tensor chorioideae in Birds and Reptiles are striped, therefore, according to the generally accepted notion, voluntary.³

Page 102, 103. “The reversed transition (viz. that the arrectores pili⁴ might have been primordially unstriped and have become voluntary) would not have presented any great difficulty.”

It may be so; but I rather doubt that you are right in basing this conclusion, as you seem inclined to do, on the fact that “the voluntary muscles are in an unstriped condition in the embryos of the higher animals.” Most likely both forms are connected in some way, taking the evolution of the animal kingdom at large; but just in the higher animals they have become distinct morphological elements with different development, so that we are not entitled to say in any way, that the unstriped muscles of the higher animals are developmental stages of the striped ones. On the whole I should rather think that the arrectores pili are parts or remnants of the large system of cutaneous muscles, which were primordially, as parts of the muscular system of the trunk, striped   But as they lost gradually the connection with the nervous centres of the will, their histological form changed and with this of course also the form of their development.

On pages 34, 64 and 142 you mention some actions, all of which seem to me to belong to one great principle, although I am unable to state it with precise words. P. 34. you say that “some actions are due to imitation or some sort of sympathy”. I think the imitation is the most important element, but not only the imitation of an action performed by some one else; any other movement, also one’s own, is imitated, or accompanied by a similar one, especially if a person wishes to enforce or secure a certain movement. Here that comes in what you call the association of our intentions and movements, but besides this also the symmetry of our whole structure and the sense of rhythm. I think one and the same principle of imitation, with the tendence to enforce, is to be seen: in the billard-player (p 64), in the child learning to write (p 34. I twisted my tongue when I was learning to play the violin, my daughters do it in writing, drawing, playing the piano), in a person trying to thread a needle (p 142.). Here the mouth is closed and generally pointed as if one could help the thread to go through the eye   But try to break a hard biscuit with your hands; then you bite your teeth hard upon each other and open the mouth a little on one side as if to help the cracking. When a nervous lady sees that some one (f. i. one dancing on a rope) is about to fall, she gets hold of the next object, may it be her neighbours arm, imitating as it were that action which the falling person ought to or will perform. Whenever I go in a street and some other men goes close before or behind me, so that I hear or see his footsteps, I cannot help to fall unconsciously into the same time or rhythm of his steps, so that I keep pace with him   Of course I get aware of it immediately and am vexed about it, but then I must make some effort to have my own ‘tempo’. I knew a nice little intelligent girl, the daughter of an eminent embryologist, now, may be, an elderly lady. When her father told her a little story, however simple and childish it might have been, as soon as he began to open his mouth, to frown, and exaggerate his expessions of anger, astonishment, terror or laughter, without their being connected in the least with the tale, the intensely attending girl imitated all these expressions most ludicrously and quite unconsciously. Persons listening to music are always very apt to nod in the rhythm of the piece.

p. 275. I never noticed with the common Sicilians and Neapolitans any other sign used as a negative than a “throwing back of the head with a cluck of the tongue”, just so as you say it is used by the modern Greeks and Turcs. I always thought that these forms, nodding and throwing back of the head were the expressions which the Romans called adnuere and abnuere.⁵

I beg your pardon for offering you these trifles. There are some more formal questions, which you would oblige me to answer by and by occasionally.

P. 121 in the quotation from Somerville; must it not be ‘sloe-black’ instead of ‘sloe-back’, the meaning of which I cannot guess.⁶

On p. 79 you give some passages from Shakespeare.⁷ I read Hamlet, Othello, Macbeth, the Richards, Taming the Shrew, but could not find them   Have you the places or can you at least tell me the play? As we have an “authorized version” so to say, I should like to give the quotation in the words of this.⁸ But don’t trouble about it.

p. 149. note 3, line 5. Wouldn’t it be better to put the I referring to a special muscle, outside the brackets? As it stands there within “(I. p. 24)”, it looks just like a Roman numeral⁹

You need not send me clean sheets, unless they do contain new alterations, not contained in the second revise. Perhaps you will send me afterwards a clean copy of the book when it is out.¹⁰

I am now hard at work with the concluding part of my Handbook of Zoology.¹¹ When this is done I had a great mind to get at the Geographical Distribution of Animals, for which we have only special treatises and nothing very comprehensive   But before I can think of this, I shall try to see you at last. As I am asked to give the course of lectures in Edinburgh as substitute for Professor Wyville Thomson, I come through London next April.¹²

With the best wishes for your health, believe me, | My dear Sir, | Yours very sincerely, | J. Victor Carus