( ci^ ) 



suggest a change — and I think a desirable change — in the 

 statement of the problem. For the question, " Are acquired 

 characters hereditary 1 " it would be more accurate to sub- 

 stitute " Can the acquired characters of the parent be handed 

 down as inherent characters in the offspring 1 " 



It is in no way necessary that the acquired elements of a 

 character should be disentangled from the inherent elements, 

 so that we can prove the character as a whole to be dependent 

 upon a controllable external cause, and therefore itself con- 

 trollable. In fact we speak of a character as "acquired" just 

 as we speak of an article as " manvifactured," although the 

 result itself is a complex of the properties of natural 

 substances and of changes introduced by art.* 



Lamarck^s Second Law a contracUctio7i of his First Law. — 

 Before leaving these general introductory considerations 

 and proceeding to weigh the evidence offered by the insect 

 world, it is of importance to demonstrate that thei^e is an in- 

 consistency in the teaching of Lamarck and his followers 

 which, startling as it is, was never noticed until pointed out 

 by Professor E. R. Lankester in 1894.t 



" Normal conditions of environment have for many thou- 

 sands of generations moulded the individuals of a given species 

 of organism, and determined as each individual developed and 

 grew ' responsive ' quantities in its parts (characters) ; yet, as 

 Lamarck tells us, and as we know, there is in every individual 

 born a potentiality which has not been extinguished. Change 

 the normal conditions of the species in the case of a young 

 individual taken to-day from the site where for thovisands of 

 genei-ations its ancestors have responded in a perfectly defined 

 way to the normal and defined conditions of environment ; 

 reduce the daily or the seasonal amount of solar radiation to 

 which the individual is exposed ; or remove the aqueous 

 vapour from the atmosphere ; or alter the chemical composi- 

 tion of the pabulum accessible ; or force the individual to 

 previously unaccustomed muscular effort or to new pressures 



* For an interesting discussion on the relation between "acquired" 

 and "genetic" characters see Adam Sedgwick's Presidential Address to 

 Section D of the British Association at Dover (Report 1899, pp. 759-766). 



t "Nature," vol. li, 1894, p. 102. 



