14 Professor Gregg Wilson on 



(lation, but from the edge of the iris. Such facts certainly tempt 

 one to conclude that organisms possess a definite purposivencss 

 that cannot be explained by natural selection. 



Lastly, I would lay stress on the fact that the mechanistic 

 theory of natural selection does not explain the individuality of 

 organisms, and particularly of multicellular organisms. There is 

 an individuality which, as C. M. Child says,* " is distinctive of 

 the living organism, which determines harmonious development 

 and functional unity throughout the continuous dynamic change 

 which constitutes life." Child attempts to explain this as ulti- 

 mately resulting from the relations between living protoplasm and 

 the world external to it ; but he also regards this individuality 

 as the dominant not the subordinate or casual. He recognises 

 that the orgatu'sm is a unit in inheritance and development.— not 

 a mere assemblage of cells. And it is because of this recognition 

 that he says we must expect to find that so-called 'acquired 

 characters ' may be impressed on the organism to such a degree 

 that sooner or later the reaction system may give rise to these 

 characters without the action of the particular external factor 

 which originally produced them. An individuality of this kind 

 is certainly not accounted for by the orthodox mechanistic 

 philosophy. 



It is not surprising that there are numerous rival theories 

 to the Weismannic one. Oscar Hertwig has all along seen the 

 difficulties of Weismann's view of the germ-plasm and of develop- 

 ment, and has given credit to position as determining the fate of 

 a cell in development ; and others have held similar views. But 

 while there probably never before was such appreciation of the 

 perfection of mechanisms in the organismt there seems to be an 

 even fuller recognition of the distinctiveness of organisms. 



Some thinkers, like the metaphysical physiologist Haldane, i 

 go the length of proclaiming that this world, with all that is 



* " Iiulividualitj' in Organisms." Chicago, 1915. 



t See Prof. D'Arcy Thompson : " Growth and Form."' 1917, 



J" Mechanism, Life, and Personalitj'. " 1913, 



