P.S.-If possible, I should much like to attend the funeral. Can you let me hear as to this?

To Professor Poulton.

18 Cornwall Terrace, Regent's Park, N.W.: January 27, 1890. My dear Poulton,-Many thanks for your letter, with its very clear and cogent reasoning. But I am not sure that the latter does not hit Weismann harder than it hits me. For the cases you have in view are those where very recently acquired characters are concerned; and where, therefore, according to my views, the force of heredity' is weak and thus quickly worn out.' In such cases (as I say in the last passages of enclosed, which I return for you to hand me on Friday) cessation will (quickly) ensure the reduction of an unused organ below fifty per cent. of its original size, and so on down to zero; but this it does because it is now assisted by another and co-operating principle-viz. the eventual failure of heredity.'

Now, it is just this co-operating principle that Weismann is debarred from recognising by his dogma about 'stability of germ-plasm.' And it is a principle that must act the more energetically (i.e. 'quickly') the shorter the time since the now degenerating organ was originally acquired. In the 'Nature' articles I was speaking of rudimentary organs' which in Darwin's sense are very old heirlooms. All this to make you reconsider whether there is any disagreement between us upon this point.

It is, indeed, a terrible thing about Aubrey Moore, and also a loss to Darwinism on its popular side.

G. J. R.

February 16, 1890.

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After receiving your letter this day a month ago, it occurred to me that I had better write an article in 'Nature' on Panmixia, pointing out the resemblances and the differences between Weismann's statement of the principle and mine. Shortly after sending it in, Weismann's answer to Vines appeared, and from this it seems that he has modified his views upon the subject. For while in his essays he says that the complete disappearance of a rudimentary organ can only take place by the operation of natural selection. (i.e. reversal of selection through economy, &c.), in Nature' he says, 'Organs no longer in use become rudimentary, and must finally disappear, solely by Panmixia.' Thus, the same facts are attributed at one time 'only' to the presence of selection, and at another time 'solely' to its absence.

Now, the latter view seems exactly the same as mine, if it means (as I suppose it must) that the cessation of selection ultimately leads to a failure of heredity. (How about stability of germ-plasm here?) The time during which the force of heredity will persist, when thus merely left to itself, will vary with the original strength of this force, which, in turn, will presumably vary with the length of time that the organ has previously been inherited. Thus, differences of merely specific value (to which you allude in your letter) will quickly disappear under cessation of

selection, while vestiges' of class value are longenduring. The point to be clear about is that the cessation of selection (in my view) entails two consequences, which are quite distinct. First, a comparatively small amount of reduction due to promiscuous variability round an average which, however, will be a continuously sinking average if the cessation is assisted by a reversal of selection; and second, later on, a failure of the form of heredity itself.

Touching the first of the two consequences, you say that 'variations below or away from the standard would not be balanced by those above, because the standard was reached by the selection of such an extremely minute fraction of all variations which occurred.' But can variations in the matter of increase or decrease take place in more than two directions, up or down, smaller or larger, better or worse? (Read Wallace, 'Darwinism,' pp. 143 4.)

I write this in view of the lecture you say you are going to give, because I do not know when 'Nature will bring out my article.

March 20, 1890.

It might perhaps be well for you to read the typewritten reply which I have prepared to Wallace's But this is criticism on physiological selection.' for you to consider. to consider. He has fallen into some errors of great carelessness, not only with regard to my but also to that of Mr. Gulick, whose theory of paper, segregate fecundity' is the same as mine. On this account I am able to upset the whole criticism, and, bottom upwards, to show that it really supports the theory.

เ

I see Nature' of this week contains my letter on Panmixia, and hope it will define in your and other minds the outs and ins of the matter.

Please return the enclosed, which I send as a fact that may interest you.

To Professor J. C. Ewart.

18 Cornwall Terrace, Regent's Park, N.W.: April 27, 1890. As Ethel has already told you, I believe, we have taken a three years' lease of a charming old house, and let this one for a corresponding period. It is a very old house in Oxford, having been built by Cardinal Wolsey. It is immediately opposite Tom Tower of Christ Church, and full of old oak-walls, floors, and ceilings of the principal rooms being nothing else.

I do wish you could come up before we begin operations, to give us the benefit of your advice how so splendid an opportunity in the way of decoration should be utilised. We have to get out of this house, with all our furniture, on or before May 20. The children and servants will then go to Geanies, while my wife and I will go to Oxford to begin the decorations.

I am preparing my lectures on Darwinism for the press, so that they may be ready for publication on the last day of my course at Edinburgh in November. I suppose I have your permission to reproduce your R.S. pictures of electric organs? Also, could you send me for a day or two Haddon's book on Embryology?

I have just heard that Charles Lister (whom I