Letter to Charles Darwin October 11, 1871
To the Same.
CAMBRIDGE, Oct. 11, 1871
I have for some time past been so absorbed in the preparation of a memoir on the uses and origin of the arrangements of leaves in plants, that almost every other interest has been put aside ; and I have delayed longer than I should, to acknowledge the receipt of the pamphlets you were so kind as to send me. The title-page is much more eye-catching than I anticipated; and altogether the pamphlet appears in a very taking dress. The printer's art may make up in part for defects in the style of the essay, which certainly is not of a pamphleteering sort.
I presented to our Academy last evening my memoir on Phyllotaxy and other points in the structure of plants,---which has become a much more elaborate essay than I expected. It is quite as long as the pamphlet, though the length is partly due to details and considerable repetitions, by which I have tried to give it a popular character. It was well received, and will soon be printed, when I will send you copies. The structure of plants has for a long time seemed to me as likely to afford one of the easiest, though by no means an absolutely easy, example of the use of the theory of Natural
( 235) Selection as a working hypothesis ; but I was not well qualified for working it out. I have not, for example, seen the Essay on Plants by Nageli, to which you refer, and may not be aware of many of the difficulties of the problem ; but I have not ignored any that I knew, and on points in physiology I have consulted Professor Gray. I have arrived at very different conclusions from those of that essay (if I can judge from your reference to it), in respect to the range of adaptive characters in plants.
With the resources of hypothesis afforded by the mathematical, mechanical, and physiological principles known to me, I have attempted the explanation of the special features of Phyllotaxy as present adaptations ; also explanations of two genetic characters in plants, the general spiral and the whorl arrangements, as past adaptations ; and have proposed to reduce the distinction of adaptive and genetic characters in general to a merely relative one. Regarding the latter as inherited features of past and outgrown adaptations, and conjecturing what some of these could have been, I have built an hypothesis across the chasm between the higher plants and sea-weeds. This sounds venturesome and paradoxical enough, much more so, I hope, than it will appear in the essay, where I feel the way along with at least some appearance of caution. . . .
On October 23, Mr. Darwin wrote: "It pleases me that you are satisfied with the appearance of your pamphlet. I am sure that it will do our cause good service ; and this same opinion Huxley has expressed to me. . . . Your letter arrived just one day after the return of my two sons from America. They enjoyed their tour exceedingly, and, I think, Cambridge more than all the rest. I am sure I feel grateful for the extraordinary kindness with which they were treated."
And again, on April 6, 11872, he acknowledges the receipt
( 236) of the paper on Phyllotaxis: "I have read your paper with great interest, both the philosophical and special parts. I have not been able to understand all the mathematical reasoning; for irrational angles produce a corresponding effect on my mind. Nevertheless, I have been able to follow the general arguments ; and I am delighted to have a cloud of darkness largely removed. It is a great thing to be able to assign reasons why certain angles do not occur, or occur rarely. I have felt the difficulty of the case for some dozen years. Your memoir must have been a laborious undertaking; and I congratulate you on its completion. The illustration taken from leaves of genetic and adaptive characters seems to me excellent, as indeed are many points in your paper. . . . I sent you some time ago a copy of my new edition of the ` Origin,' which 1 hope you have received."