Dear Mr. Darwin,—I should very much like to see the papers to which you allude. A priori one would have thought the bisecting plan the more hopeful, but if the other has yielded positive results, in the case of an eye and tubers, I think it would be worth while to try the effect of transplanting various kinds of pips into the pulps of kindred varieties of fruit; for the homological relations in this case would be pretty much the same as in the other, with the exception of the bud being an impregnated one. If positive results ensued, however, this last-mentioned fact would be all the better for 'Pangenesis.'
You have doubtless observed the very remarkable case given in the 'Gardener's Chronicle' for January 2—I mean the vine in which the scion appears to have notably affected the stock. Altogether vines seem very promising; and as their buds admit of being planted in the ground, it would be much more easy to try the bisecting plan in their case than in others, where one half-bud, besides requiring to be fitted to the other half, has also to have its shield fitted into the bark. All one's energies might then be expended in coaxing adhesion, and if once this were obtained, I think there would here be the best chance of obtaining a hybrid; for then all, or nearly all, the cells of the future branch would be in the state of gemmules. I am very sanguine about the buds growing under these circumstances, for the vigour with which bisected seeds germinate is perfectly astonishing.
Very sincerely and most respectfully yours,
Geo. J. Romanes.
P.S.—I have been to see Dr. Hooker, and found his kindness and courtesy quite what you led me to expect. Such men are rare.
April 21, 1875.
In returning you ——'s papers, I should like to say that the one on 'Inheritance' appears to me quite destitute of intelligible meaning. It is a jumble of the same confused ideas upon heredity about which I complained when you were at this house. How in the world can 'force' act without any material on which to act? Yet, unless we assume that it can, the whole discussion is either meaningless, or else assumes the truth of some such theory as 'Pangenesis.' In other words, as it must be 'unthinkable' that force should act independently of matter, the doctrine of its persistence can only be made to bear upon the question of heredity, by supposing that there is a material connection between corporeal and germinal cells—i.e. by granting the existence of force-carriers, call them gemmules, or physiological units, or what we please.
Lawson Tait says (p. 60)—'The process of growth of the ovum after impregnation can be followed only after the assumption either expressed or unconsciously accepted of such a hypothesis as is contained in Mr. Darwin's "Pangenesis;"' and it is interesting, as showing the truth of the remark, to compare, for example, p. 29 of the other pamphlet—for, of course, 'Pangenesis' assumes the truth of the persistence of force as the prime condition of its possibility. If ever I have occasion to prepare a paper about heredity, I think it would be worth while to point out the absurdity of thinking that we explain anything by vague allusions to the most ultimate generalisation of science. We might just as well say that Canadian institutions resemble British ones because force is persistent. This doubtless is the ultimate reason, but our explanation would be scientifically valueless if we neglected to observe that the Canadian colony was founded by British individuals.
The leaf from 'Nature' arrived last night. I had previously intended to try mangold-wurzel, as I hear it has well-marked varieties. The reference, therefore, will be valuable to me.
Before closing, I should like to take this opportunity of thanking you again for the very pleasant time I spent at Down. The place was one which I had long wished to see, and now that I have seen it, I am sure it will ever remain one of the most agreeable and interesting of memory's pictures.