( Ixxx ) 



fact that their inmost couvictious on matters of the deepest 

 scientific importance are to be read, often in the compass of 

 a brief sentence. There we find, as we cannot find in any 

 other way, the real core of the matter, with all accessory and 

 surrounding considerations stripped away from it.* A care- 

 ful study of the two recent volumes of Darwin's letters, and 

 a re-study of the three earlier volumes, with a view to this 

 Address, have shown how Darwin's thoughts were again and 

 again occupied upon subjects bound up with the problem I 

 have ventvired to bring before you this e%'ening. The interest 

 reaches its height when we find that strongly-marked differ- 

 ences of opinion on fundamental questions are threshed out 

 in the correspondence, when we see, as I shall have occasion 

 to point out in greater detail in the later pages of this Address, 

 Darwin differing sharply from Huxley on the one hand, and 

 with Wallace on the other, as to the significance and history 

 of sterility between species. 



In such episodes we are permitted to become the witnesses 

 of a supremely interesting struggle, where the central figure 

 of modern biological inquiry is contending with his chief 

 comrades in the great fight, — with the co-discoverer of natural 

 selection, with the warrior hero who stood in the forefront of 

 the battle. 



The correspondence of Charles Darwin has a further deep 

 interest for us. We see the means by which a gentle, 

 sympathetic, intensely human nature overpassed the stern 

 limits imposed by health, and was able to impart and to 

 receive fresh ideas, and a stimvilus ever renewed — the im- 

 pulse to varied and unceasing research. I have lately been 

 studying with keen interest the life of another great English- 

 man, William John Burchell,t than whom no better equipped 

 or more learned traveller ever explored large areas in two 

 continents. When I state that searching inquiry has only 

 brought to light a dozen of his letters, and that he was 

 known to hardly any of the great naturalists of his day, we 

 see the reason for the sad, unproductive, brooding close of a 

 career which opened with almost unexampled brilliancy and 



* "Quarterly Keview," January 1901, p. 258. 

 t "Ann. and Mag. Nat, Hist.," January 1904, p. 45. 



