316 SIR JOSEPH DALTON HOOKER 



whole-hearted adherent. But he was also Darwin's constant 

 and welcome adviser and critic. Well indeed was it for the 

 successful launch of evolutionary theory that old-fashioned 

 systematists took it in hand. Both Darwin and Hooker had 

 wide and detailed knowledge of species as the starting-point of 

 their induction. 



Before we trace the part which Hooker himself played in the 

 drama of evolutionary theory, it will be well to glance at his 

 personal relations with Darwin himself. It has been seen how 

 he read the proof-sheets of the Voyage of the ' Beagle' while still 

 in his last year of medical study. But before he started for the 

 Antarctic he was introduced to its author. It was in Trafalgar 

 Square, and the interview was brief but cordial. On returning 

 from the Antarctic, correspondence was opened in 1843. In 

 January 1844 Hooker received the memorable letter confiding to 

 him the germ of the Theory of Descent. Darwin wrote thus : 

 " At last gleams of light have come, and I am almost convinced 

 that species are not (it is like confessing a murder) immutable: 

 I think I have found (here's presumption !) the simple way by 

 which species become exquisitely adapted to various ends." 

 This was probably the first communication by Darwin of his 

 species-theory to any scientific colleague. 



The correspondence thus happily initiated between Darwin 

 and Hooker is preserved in the Life and Letters of Charles 

 Darwin, and in the two volumes of Letters subsequently pub- 

 lished. They show on the one hand the rapid growth of a deep 

 friendship between these two potent minds, which ended only 

 beside the grave of Darwin in Westminster Abbey. But what 

 is more important is that these letters reveal, in a way that none 

 of the published work of either could have done, the steps in the 

 growth of the great generalisation. We read of the doubts of 

 one or the other ; the gradual accumulation of material facts ; 

 the criticisms and amendments in face of new evidence; and the 

 slow progress from tentative hypothesis to assured belief. We 

 ourselves have grown up since the clash of opinion for and 

 against the mutability of species died down. It is hard for us 

 to understand the strength of the feelings aroused : the bitterness 

 of the attack by the opponents of the theory, and the fortitude 



