990 LIFE : OUTLINES OF GENERAL BIOLOGY 



It would be fallacious to argue directly to man from any of the 

 biological illustrations above given ; yet surely enough has been said 

 to suggest the undesirability of losing faith too utterly in the potency 

 of nurture in shaping the individual life, be this organic or human. 

 Of the danger of arguing from one case to another, let us give an 

 interesting illustration concerning the influence of alcohol. D. D. 

 Whitney studied the effect of minute traces of alcohol in the water 

 in which Rotifers or Wheel Animalcules were kept. The result was a 

 decrease in reproductive power, and a weakening in the power of 

 resistance to deleterious influences. Twenty-eight generations were 

 studied, and the evil effects of the alcohol were proved. But from the 

 eleventh to the twenty-second generation at least it was found that 

 removal of the alcohol was followed by rapid individual recovery, 

 and that the grandchildren showed none of the defects caused by 

 alcohol in their grandparents. 



Stockard subjected male guinea-pigs for three years to vapour 

 of alcohol, which does not spoil their stomach; and he found that 

 an alcohoUsed male guinea-pig almost invariably begot defective 

 offspring, even when mated with a vigorous normal female. The 

 effects were manifest in the second generation also. "The poison 

 injures the cells and tissues of the body, the germ-cells as well as 

 other ceUs, and the offspring derived from the weakened or affected 

 germ-cells have all the cells of their bodies defective." We shaU 

 discuss this rather difficult case in another connection ; what we are 

 concerned with here is illustrating the far-reaching influence of nurture. 



In attempting to appreciate the importance of nurture for the 

 individual, emphasis must be laid on its role in the development of 

 the himian mind ; and here we are at one with many biologists and 

 psychologists of high standing who have declared that our mind is 

 in large measure a social product. One of the sanest of them. Prof. 

 G. H. Parker, writes: "Our intellectual outfit comes to us more in 

 the nature of a social contribution than an organic one." While our 

 mental capacity is primarily determined by heredity, it can be 

 encouraged and augmented, or inhibited and depressed, within wide 

 limits, by nurture. 



Especially as regards the mind do we feel that while the inherit- 

 ance is the seed-corn, "nurture" is the soil and the sunshine, the 

 wind and the rain. Nurture can create nothing, but without its 

 favouring conditions our sowings fail; and the buds may fail to open, 

 or to unfold freely, or later to blossom, or to fruit, or these to seed 

 anew. We cannot make a silk purse out of a sow's ear, but by trading 

 with our talent we may make it two, or peradventure five or ten 

 talents. If man cannot add to his inheritance any new kind of talent 

 for which he has no initiative or hereditary factor (if this indeed be 

 possible?), he can certainly and vastly increase the value and the 

 effectiveness of the talents with which he is born. 



