120 THE CONTROL OF LIFE 



philosophy." In the opinion of Professor Bateson, than 

 whom none has more right to be listened to, it is a reason- 

 able view that environmental change may lead to abnor- 

 mal divisions in the ripening germ-cells, and that these 

 abnormal cell-divisions are the starting-points of new 

 varieties. Broadening this, we may suggest that 

 changes in nurture may have an unsuspected impor- 

 tance as the liberating stimuli of germinal variations. 



(5) The quality of nurture, which is largely in Man's 

 own hands, determines the degree to which the buds of 

 good qualities in our inheritance may be made to unfold, 

 and the buds of bad qualities may be kept more or less 

 dormant. We do not know — when we are young, at 

 any rate — all that is in our inheritance ; it is common- 

 sense to give it every chance, with as varied a nurture 

 as we can. This is one of the reasons for embarking 

 on adventure, when there is opportunity, before our 

 voyaging is narrowed down to a stated course. As 

 long as we are young at least — we discover ourselves 

 gradually — we do not know all that is in our inheritance j 

 the common-sense advice is not to take too many 

 chances, not to play with fire, and to let sleeping dogs 

 lie, if we can. 



(6) For the individual there is great plasticity as 

 the result of changes in environment and function. 

 Man is very modifiable and educable. And though the 

 resulting modifications do not seem to be transmissible 

 as such, they can be reimpressed, if desirable, on genera- 

 tion after generation. In her interesting study. Environ- 

 ment and Efficiency (1912), Miss Mary Horner Thomson 



