To Ernst Haeckel 18 August 
Down. | Bromley. | Kent. S.E.
My dear Sir
I received a few days ago a sheet of your new work, & have read it with great interest.1 You confer on my book, the “Origin of Species”, the most magnificent eulogium which it has ever received, & I am most truly gratified, but I fear if this part of your work is ever criticized, your reviewer will say that you have spoken much too strongly.2 Your abstract seems to me wonderfully clear & good; & one little fact shews me how clearly you understand my views, namely your bringing prominently forward, which no one else has ever done, the fact & the cause of Divergence of Character.3 Oddly enough, as it now appears to me, it was many years before I clearly saw the necessity of admitting a tendency to divergence of character, & some more years until I could see the explanation.4
I have read with much interest your discussion on Inheritance &c; & all the more so as I give in my next work, which will not be published for half a year, several chapters on this & other allied subjects.5 So that I shall feel very curious to read your remaining chapters when published; but it is a terrible evil to me that I cannot read more than one or two pages at a time of German, even when written as clearly as is your book.
I suppose you have seen Prof. Claus new work on Copepoda in which he discusses individual variability, & alludes to your work; I have been interested by it.6 I heartily congratulate you that your great undertaking is so nearly completed & with my cordial thanks for the great honour which you have done me & with a full belief that you will do excellent service in the cause which we have both at heart, I remain my dear sir | yours very sincerely Ch. Darwin
Comments on sheet of EH’s Generelle Morphologie . In emphasising divergence of character EH shows his clear understanding of CD’s views. It was years before CD saw necessity of divergence.
Interested in Carl Claus [Copepodenfauna von Nizza (1866)].