1908. The British Association in Dublin. 211 



PROCEEDINGS OF THE ASSOCIATION. 



THE PRESIDENTIAL ADDRESS. 



Dublin was supremely fortunate in entertaining the British 

 Association in the year of Francis Darwin's presidency, a5^ear 

 which marked the jubilee of the theory of Natural Selection 

 as promulgated in July, 1858, before the Linnean Society by 

 Charles Darwin and Alfred Russell Wallace. It was hoped 

 that the President might deal with the progress of the evolu- 

 tion idea from the work of his great father to the present time. 

 But in his openinsj remarks he declared himself '* quite un- 

 fitted" for such a "'gigantic task." Nevertheless, starting 

 from the subject of his own special work — the movements of 

 plants — he threw light from man}- points on the burning 

 biological problems of the da}-. A few quotations may give 

 an idea of the course of the argument of his most notable 

 address. 



''The fact that plants must be classed with animals as 

 regards their manner of reaction to stimuli has now become 

 almost a commonplace of biology. . . . We can as a rule 

 onl}^ know the stimulus and the response^ while the inter- 

 mediate processes of the mechanism are hidden in the secret 

 life of the protoplasm. We might, however, have guessed 

 that big changes would result from small stimuli since it is 

 clear that the success of an organism in the world must 

 depend, partl}^ at least, on its being highly sensitive to 

 changes in its surroundings. . . . Morphological alter- 

 ations produced by changes in environment have been brought 

 under the rubric of reaction to stimulation, and must be con- 

 sidered as essentially similar to temporary movements. The 

 very first stage in development may be determined by a purely 

 external stimulus. . . . Klebs kept Saprolegnia mixta in 

 uninterrupted vegetative growth for sixyearri ; while by remov- 

 ing a fragment of the plant and cultivating it in other con- 

 ditions the reproductive organs could at any time be made to 

 appear. 



" If a sleeping plant is placed in a dark room after it has 

 gone to sleep at night, it will be found next morning in the 



A 2 



