172 DARWINISM AND HUMAN LIFE 



leaves. Semon exposed them to artificial days and 

 nights of six hours' or twenty-four hours' duration ; 

 but the plants exhibited the twelve-hours' cycle 

 quite unmistakably — just a little altered. After 

 this experiment Semon exposed the plants to 

 continuous darkness or continuous illumination. 

 The twelve-hours' cycle still manifested itself for 

 a time, but gradually became indistinct. Here 

 we see the inherited nature struggling, as it were, 

 against inappropriate nurture. 



(6) Although modifications do not seem to be 

 transmitted as such, or in any representative degree, 

 there is no doubt that they or their secondary 

 results may in some cases affect the offspring. 

 This is especially the case in typical mammals, 

 where there is before birth a prolonged (placental) 

 connection between the mother and the unborn 

 young. In such cases the offspring is for a time 

 almost part of the maternal body, and hable to be 

 affected by modifications thereof — e.g. by good 

 or bad nutritive conditions. In other cases, also, 

 it may be that deeply saturating parental modifica- 

 tions, such as the results of alcoholic and other 

 poisoning, affect the germ-cells, and thus the 

 offspring. A disease may saturate the body with 

 toxms and waste-products, and these may provoke 

 prejudicial germinal variations. 



(c) Though modifications due to changed 

 " nurture " do not seem to be transmissible, they 

 may be reimpressed on each generation. Thus 

 " nurture " becomes not less, but more, important 

 in our eyes. " Is my grandfather's environment 

 not my heredity ? " asks an American author 

 quaintly and pathetically. Well, if not, let us 

 secure for ourselves and for our children those 



