WCP6800

Letter (WCP6800.7872)

[1]

Granies, Rossshire

July 19/[18]90

Dear Mr. Gulick,

Changing my residence from London to Oxford, and immediately afterwards from Oxford to Scotland, has prevented me from again reading your letter of April before last replying to you letter of June. Therefore, having now read the former once more, I write again to say that I quite understand the distinction which you draw between Elemental Segregation where this occurs in the form of Potential or Pre-potential Segregation, and where it does so in the form of Segregate Fecundity. But still I am not satisfied that if it can act alone in the former case, it may not likewise do so in the letter. (I have submitted your calculations on the subject in your first L.S. [Linnean Society] paper to Mr. Moulton, and he thinks he has detected an over-sight in them. I will forward his examination of them if you like). The point, however, is one of comparatively small importance, and when the general body of our agreement is so great, we need not distress ourselves about this "little member" of the reverse.

I have been again particularly struck by the extraordinary coincidence of our thought while reading your MS. reply to Mr. Wallace — which is so identical in substance with the one which I have prepared for press, that I intend to quote parts in a Postscript in order to show the correspondence. Then I shall post it to Prof. Dana — i.e. tomorrow.

Regarding Wallace's criticism there is one point I should like you to consider. He professedly bases the whole of his supposed new theory of cross-sterility on the comparative infertility or other infertility of the hybrids [2] — i.e. on your segregate fecundity (because failure to produce fully fertile progeny is so far measure for measure equivalent to not producing progeny at all), and segregate vigour[?]. Now, at first sight it seems as if infertility or other inferiority of hybrids cannot re-act on the sexual systems of parent forms so as induce in them any further degrees of incompatibility (e.g. that sterility of mules[?] and [illeg.] cannot lessen the fertility of first crosses between horse asses and mares, or between horses and she-asses). And, as far as anything that occurs in Wallace's argument, the matter might rest there. But is there not a possibility which he has not mentioned, whereby absence of fertility or want of vigour on the part of progeny may re-act in the sexual system of parent forms? For in the measure that a cross A x B yields sterile or inferior offspring, the individuals A and B are failing to assert their influence on the next generation; when a more fortunate cross C x D becomes a leaves a better progeny to inherit thus the more fortunate (or better co-ordinated) sexual systems. Have you considered this point, and, if so, with what result?

I have been thinking still further over the matter of terminology; and it seems to me best to retain "Physiological Solution" in its original signification — i.e., as equivalent to your "Physiological Segregation" in the particular case where varieties and resulting species are concerned. If a separate term is needed for "the principle by which correspondence between the male and female elements of an [3] interconnecting group is maintained, I think it best to employ your suggested "Elemental Co-ordination".. But, as explained in my last letter, it appears to me much more important to distinguish between Physiological Segregation when first arising as between varieties and species, and when fully established as between genera etc., than it is to distinguish between Physiological Segregation in general and Elemental Coordination. For it is the former distinction which has hitherto been so completely over-looked. Naturalists — even in pre-Darwinian days — have always known and recognized that sterility when fully present keeps species etc. physiologically isolated; and therefore evolutionists have always perceived that it constitutes a negative condition to divergence of all groups higher than species. But what they have not hitherto perceived is, that it con in its earlier stages it constitutes the segregating cause, or it itself explains the origin of such species as arise in consequence — while the genera, etc. which afterwards arise do so on account of additional causes of segregation superimposed on the <now> given condition of cross-sterility. It is for the purpose of mastering this — to my mind — most important of all distinctions where "Physiological Segregation" is concerned, that I should like to return the term "Physiological Solution" where alone that term is applicable.

Again, I am not sure that "Isogamy" would be so good an equivalent of your "Separate Breeding" as the word "Apogamy". [4] Suppose the latter were adopted, the scheme would be thus:—

Isolation
Discriminate Indiscriminate
Homogamy Apogamy

Under each of these elements all your many sub-divisions would come.

I have now grown to be as satisfied about the truth of our common views as I am about the general theory of evolution itself. And I cannot quite make up my mind whether to feel glad or sorry that so far there is only one other human being who fully understands them. For it must only be a question of time, and opposition now may prevent "We always told you said so" hereafter. But what I most desire to get accomplished is experimental proof. If you learn of botanists in any part of the world who would help in this, I hope you will try to get them to work on Jordan's lines. It is astonishing how far he has verified our views by anticipation.

Yours very truly, | Geo. J. Romanes [signature]

Please cite as “WCP6800,” in Beccaloni, G. W. (ed.), Ɛpsilon: The Alfred Russel Wallace Collection accessed on 29 March 2024, https://epsilon.ac.uk/view/wallace/letters/WCP6800