20 THE PRESIDENTIAL ADDRESS 



are of great value and often provide the only available evidence. 

 There are, however, instances in which abundant data for statistical 

 investigation are furnished by the wild animals themselves. Thus 

 the long-eared bat has the convenient habit of eating moths — its 

 regular food — while it hangs suspended from a surface to which it 

 returns after each capture ; and as the wings are rejected, these may 

 be collected in large numbers, yielding valuable information on the 

 significance of concealing and warning patterns. 



In the attempt to determine the motive causes of organic evolu- 

 tion, the work of the naturalist, the student of living nature, is 

 essential. His task is to do what Lyell did for geology by directing 

 attention to the forces now in operation and seeking with their help 

 to interpret the past. By the death of Lord Rothschild, on 

 August 28, the world has lost a great naturalist who devoted his life 

 to the creation of a splendid museum offering unique opportunities 

 for the study of modifications which arose as the species of an 

 important Insect Order (Lepidoptera) gradually spread over the 

 areas which they now occupy. It was his wish that this immense 

 field for research upon these latest phases of evolutionary change 

 should become the property of the Nation, forming a magnificent 

 addition to the British Museum. I feel confident that it is the 

 earnest hope of us all that Lord Rothschild's wish may be realised 

 and that this great memorial of a life devoted to Natural History 

 will provide constant inspiration to many workers in the same 

 branch of science. 



Associated with these researches is the study of adaptations 

 which have been developed in recent times and can, in certain 

 instances, be proved to undergo changes even now. Thus the 

 interesting observations of H. Lyster Jameson showed that a pale 

 local race of the common mouse had been formed, although in- 

 completely, in from 100 to 125 years, by the selective attacks of owls 

 and hawks on sandhills near Dublin.^" I have long believed that 

 the colours of animals provide one of the most fruitful fields in 

 which to pursue these investigations, and I regret that this work has 

 been recently attacked by an American zoologist who, referring to 

 the recent revival of natural selection, continues — ' if the doctrine 

 can emerge minus its sexual selection, its warning colors, its 

 mimicry and its signal colors, the reaction over the end of the century 

 will have been a distinct advantage.' ^^ It is of course impossible 

 to discuss, on the present occasion, this confident attempt to de- 

 preciate the value of work associated with the names of Darwin, 

 Bates, Wallace, Trimen and Fritz Miiller. I will only point out 



^0 Journ. Linn. Soc. (Zool.), vol. 26, 1898, p. 465, pi. 30. 

 2' Evolution. A. Franklin Shull. (New York, 1936.) 



