xx THE INFLUENCE OF ENVIRONMENT 409 



effects of the alcohol were proved. But from the llth 

 to the 22nd 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. 



Quite on the other side, however, are the experiments 

 of Stockard, who subjected male guinea-pigs for three 

 years to vapours of alcohol, which does not spoil their 

 digestion, and found that an alcoholised male guinea-pig 

 almost invariably begets 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 cells, and the offspring derived from the 

 weakened or affected germ-cells have all the cells of 

 their bodies defective. 



In estimating the importance of nurture for the indi- 

 vidual we must think of its role in the developing human 

 mind. Many biologists and psychologists are agreed in 

 the conclusion that our mind is in large measure a social 

 product. Thus Prof. G. H. Parker writes : " Our intel- 

 lectual outfit comes to us more in the nature of a social 

 contribution than an organic one." In short, 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 inheritance is the seed-corn, "nurture' is the soil 

 and the sunshine, the wind and the rain. Nurture can 

 create nothing, but without it the buds that are there may 

 fail to open or to unfold freely or to blossom. We cannot 

 make a silk purse out of a sow's ear, but by trading with 

 our talent we may make it two, per ad venture five talents. 



5. The Other Side of Heredity. The past lives on in 

 the present, that is what is meant by heredity. The 

 Hapsburg lip asserts itself after four centuries ; night- 

 blindness lingers in the Nougaret lineage since 1637 ; 

 and having all the fingers thumbs (brachydactylism) has 

 been known to persist for six generations. There is an 

 inexorableness in the transmission of all sorts of inborn 



