For the most part the younger English naturalists have accepted Professor Weismann's theory, which, by the way had long ago been anticipated by Mr. Francis Galton, and Mr. Romanes was not much supported in his opposition, or, rather, his non-adherence to Weismannism. Linnean Society, Burlington House, London, W.: March 21, 1890. My dear Dyer,--I have come to the conclusion that anything published in 'Nature' might as well never have been published at all; and therefore have come here to-day in order to look through the back numbers of 'Nature,' with a view to republishing as a small book the various things that I have contributed during the past twenty years. Thus it is I find that the explanation which I gave to Herbert Spencer _re_ Panmixia and his articles on the 'Factors of Organic Evolution,' appeared in August 25, 1887, and showed that his whole argument was in the air. I have also read my own article on Panmixia, written about two mouths ago, and published last week. The result is to satisfy me that your 'intelligent' friends must have had minds which do not belong to the _a priori_ order--_i.e._ are incapable of perceiving other than the most familiar relations. Such minds may do admirable work in other directions, but not in that of estimating the value of Darwinian speculations. A few years ago they would have thought the cessation of selection a very unimportant principle, and one which could not possibly sustain any such large question as that of the transmissibility of acquired character. And a few years hence they will wonder why they raised such an ado over the no less obvious principle of physiological selection. Yours very truly, G. J. ROMANES. He writes to his brother: 18 Cornwall Terrace, Regent's Park, N.W.: Sunday. My dearest James,--This theory, of the Non-Inheritance of Acquired Characters, is that nothing that can happen in the lifetime of the individual exercises any influence on its progeny; effects of use or disuse, for example, cannot be inherited, nor, therefore, can any adaptation to external conditions which are brought about in individual organisms. Natural selection thus can only operate in spontaneous variations of germ-plasm, choosing those variations which, when 'writ large' in the resulting organisms, are best suited to survive and transmit. This is the most important question that has been raised in biology since I can remember, and one proof of an inherited mutilation would settle the matter against Weismann's theory. I am therefore also trying the mutilation of caterpillars at the Zoo, in the hope that a _mutilation_ during what is virtually an embryonic period of life will be most likely to be transmitted, seeing that _congenital_ variations are so readily transmissible, and that these are changes of a pre-embryonic kind. All well and with much love, yours ever, GEORGE.