HEREDITY AND RADIUM AT DUBLIN 179 



tion. It has always pleased me to exalt plants in the scale of 

 organised beings ; and I therefore felt a special pleasure in 

 showing how many and what admirably well-adapted move- 

 ments the tip of a root possesses. 



That one sentence, " it has always pleased me to exalt plants 

 in the scale of organised beings," might have stood as the motto 

 both of the President's speech and of Dr. Haldane's to the 

 Physiological Section. Many of the chemists called Dr. Haldane's 

 speech retrogressive. He went near to revive the old " vital 

 principle," which did duty in old times for rational explanation, 

 and delivered some undiluted Bishop Berkeley. Sir William 

 Crooks could perhaps find in the fact an indication of the sur- 

 viving influence of Berkeley's spirit. Was he not in his day a 

 fellow of Trinity College, Dublin? But the address, which had 

 some curious analogies with the President's, was an overwhelm- 

 ing criticism of the physico-chemical view of life. The argument, 

 as most arguments this year, sprang from a consideration of 

 heredity. 



I confess (said Dr. Haldane) that as a physiologist I am 

 struck with amazement at the manner in which heredity is often 

 discussed by contemporary writers who endeavour to treat the 

 subject from a mechanistic standpoint. Sometimes, indeed, the 

 germ-cell is acknowledged to be a complicated structure, but 

 at other times it is treated as a " plasma," which can be mixed 

 with other " plasma," divided, or added to, as if for all the world 

 it were so much treacle ! I have tried to place clearly before 

 you the assumptions in connection with heredity which to my 

 mind make the physico-chemical theory of life unthinkable, 

 even if it be tenaciously clung to in connection with those 

 ordinary physiological phenomena where it has proved so 

 disappointing. 



The conception which he substitutes for the more material, 

 even in its most ingenious form of expression, is very near 

 " vital force," though it may be none the worse on that account. 



The conception which is to take its place is simply the 

 conception of the living organism, which stands, or ought to 

 stand, in the same relation to Biology as the conceptions of 

 matter and energy to Physics, or of the atom to Chemistry. 

 A living organism is distinguished by the fact that in it what 

 we recognise as specific structure is inseparably associated 

 with what we recognise as specific activity. Its activity ex- 

 presses itself in the development and maintenance of its 



