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[…] Darwin sought his assistance upon a number of points, especially upon those dealing with rudimentary structures and variations in man and the higher mammals, and the correspondence between the two men dealt mainly with matters of this kind. In one of his letters to Darwin, Turner, while pointing out that in the 'Descent of Man' a confusion had arisen in the author's mind between the supra-condyloid foramen sometimes present in the arm-bone of a man and the inter-condyloid foramen of the same bone, had evidently expressed some doubts regarding the evolutionary doctrine. Darwin's reply was as follows:

March 28, 1871,

Down, Beckenham, Kent.

I am much obliged for your kind note and especially for your offer of sometimes sending me corrections, for which I shall be very grateful. I know that there are many mistakes to which I am very liable. That is a terrible one confusing the supra-condyloid foramen with another one. This, however, I have corrected in all the copies struck off after the first lot of 2500. I daresay there will be a new edition in the course of nine months or a year, and I will correct as well as I can. As yet.

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the publisher has kept up type and grumbles dreadfully if I make many corrections. I am very far from surprised that you have not committed yourself to full acceptation of the Evolution of Man. Difficulties and objections there undoubtedly are, enough and to spare, to stagger any very cautious man who has much knowledge like yourself.

Ch. Darwin.

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Darwin's letters to Turner, though few in number, are of additional interest from the fact that they have not hitherto been published. They also illustrate one of the methods which the great naturalist employed in acquiring accurate information; they show, too, the great consideration and respect with which he treated the opinion of experts, a feature which was a marked characteristic of Darwin's attitude towards his fellow-workers.

Dec. 14, 1866,

Down, Kent.

Your kindness when I met you at the Royal Society makes me think that you would grant me the favour of a little information, if in your power.

I am preparing a book on 'Domestic Animals' and as there has been so much discussion on the bearing of such views as I hold on Man, I have some thoughts of adding a chapter on this subject.

The point on which I want information is in regard to any part which may be fairly called rudimentary in comparison with the same part in the Quadrumana or any other mammals. Now the os coccyx is rudimentary as a tail, and I am anxious to hear about its muscles. Mr Flower found for me in some work that its one muscle (with striae) was supposed only to bring this bone back to its proper position after parturition.

This seems to me hardly credible. He said he had never particularly examined this part, and when I mentioned your

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name, he said you were the most likely man to give me information. Are there any traces of other muscles? It seems strange if there are none. Do you know how the muscles are in this part in the Anthropoid Apes?

The muscles of the Ear in Man may, I suppose, in most cases be considered as rudimentary; and so they seem to be in the Anthropoids: at least, I am assured that in the Zoological Gardens they do not erect their ears. I gather that there are a good many muscles in various parts of the body which are in the same state. Could you specify any of the best cases?

The mammae in man are rudimentary. Are there any other glands or other organs which you can think of? I know I have no right whatever to ask all these questions, and can only say that I shall be grateful for any information. If you tell me anything about the os coccyx, or other structures, I hope that you will permit me to quote the statement on your authority, as that would so greatly add to its value. Pray excuse me for troubling you, and do not hurry yourself in the least in answering me.

I do not know whether you would care to possess a copy, but I told my publisher to send you a copy of the new edition of the 'Origin.'

Ch. Darwin.

Jan. 15, 1867,

Down, Bromley, Kent.

As you were so kind as to say that I might ask you a few more questions, and as my wishes are now rather more definite, I do so; but you must not suppose that I am in any hurry for an answer.

1. One or two good cases of any rudiment of a muscle would suffice; if any muscle in our arms exists in a rudimentary or nearly rudimentary condition, and which would be of service to a quadruped, going on all fours, such a case would perhaps be best.

2. You reminded me that there were two sets of muscles for moving the whole ear and its parts: which of such muscles are rudimentary in the human ear?

3. I have used your information about muscles to the os coccyx; if my memory does not deceive me, the four coccygeal bones contain spinal marrow at an early embryonic age, and afterwards it retreats. If this is so, are vestiges of the membranes of the spinal marrow retained?

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4. Is any other gland rudimentary in mankind besides the mammary glands in male mammals?

5. I may add that I have alluded to traces of the supra-condyloid foramen in the humerus of man, and to the nictitating membrane. By the way, do you chance to remember whether the nictitating membrane is well developed in Marsupials ?

Pray forgive me, if you can, for being so very troublesome.

Ch. Darwin.

Feb. 1, 1867,

Down, Bromley, Kent.

I thank you cordially for all your full information, and I regret much that I have given you such great trouble at a period when your time is so much occupied. But the facts are so valuable to me that I cannot pretend that I am sorry that I did trouble you, and I am the less so, as, from what you say, I hope you may be induced some time to write a full account of all rudimentary structures in man; it would be a very curious and interesting memoir.

I shall at present give only a brief abstract of the chief facts which you have so very kindly communicated to me, and will not touch on some of the doubtful points. I have received far more information than I ventured to anticipate.

There is one point which has occurred to me, but I suspect there is nothing in it. If, however, there should be, perhaps you will let me have a brief note, and if I do not hear I will understand there is nothing in the notion. I have included the down on the human body as the rudimentary representation of a hairy coat.

I do not know whether there is any direct functional connection between the presence of hair and the panniculus carnosus, but both are superficial and would perhaps together become rudimentary. But to put the question from another point of view: is it the primary or aboriginal function of the panniculus to move the several appendages or the skin itself?

I was led to think of this by the places (as far as my ignorance of anatomy has allowed me to judge) of the rudimentary muscular fasciculi, which you specify. Now, some persons can move the skin of their hairy hands, and is this not effected by the panniculus? How is it with the eyebrows? You specify the axilla and the front of the chest and lower part of the shoulder blades. Now these are all

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hairy spots in Man. On the other hand, the back is not hairy. So, as I said, I presume there is nothing in this notion. If there were, then rudiments of the panniculus ought perhaps to occur more plainly in men than in women.

With sincere thanks for all that you have done for me, and for the very kind manner in which you granted me your favour.

Ch. Darwin.

Although Turner's answers to these letters, unfortunately, are not preserved, the information which he was able to supply is embodied and acknowledged in 'The Descent of Man.'

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