"If I did not think you a good tempered & truth loving man I should not tell you that... I have read your book [On the Origin of Species] with more pain than pleasure. Parts of it I admired greatly; parts I laughed at till my sides were almost sore; other parts I read with absolute sorrow; because I think them utterly false & grievously mischievous— You have deserted—after a start in that tram-road of all solid physical truth—the the true method of induction. … I have written in a hurry & in a spirit of brotherly love."