PRESIDENTIAL ADDRESS. 271 



harmony with a better social environment, it will be so far 

 better than its predecessors. The race will be improved by 

 the extension and improvement of the social environment. 

 If in addition to this, the race, through inherited effects of 

 this environment, starts in each generation at a slightly 

 higher level, so much the better. But this is just the ques- 

 tion at issue — a question which can only be decisively 

 settled by reducing it to its simplest terms and applying it 

 to the touchstone of experiment and observation. 



In last week's Nature (vol. xliii., p. 581) Mr. Thistleton- 

 Dyer writes : " I have met with one plant in which I 

 thought that I had got a case of the transmission of an 

 acquired habit. Mr. Churchill procured for us seeds of 

 Arahis anachoretica^ ' a form of A. alpina^ L., with thin 

 tissue-papery leaves, growing in hollows of the rock, where 

 neither sun nor rain reach it, just as Saxifraga arachnoidea^ 

 as also Heliospermu7n glutinosum., and Zahlhruclinera para- 

 doxal all which have very thin tissue-papery leaves.' Alas, 

 on cultivation at Kew it reverted forthwith to common- 

 place Arahis alpinay This is a good illustration of the 

 influence of environment on the race. Had the seeds ger- 

 minated in the rock-hollows beyond the reach of rain and 

 sun, the leaves, it appears, would have been tissue-papery. 

 But removed to a less abnormal environment they assume 

 their ordinary form. Such a case does not necessarily dis- 

 prove use-inheritance. But it shows the extreme plasticity 

 of the individual, and it shows that the influence of the 

 normal environment is prepotent over the effects of use- 

 inheritance if such occur. It also seems to show a particu- 

 lar determinate effect of a peculiar abnormal environment, 

 not only on this plant but on others. And since the effects 

 of environment are thus seen to be potent and determinate, 

 it leads us to look in other directions than experiments with 



