408 THE STUDY OF ANIMAL LIFE CHAP. 



we can help it, spoiling good stock by bad ; but it is a 

 dubious inference that the bad is hopeless. It may often 

 be that it is not so bad as it looks. In her interesting 

 study Environment and Efficiency, 1 Miss Mary Horner 

 Thomson tells of her study of 265 children, mostly of 

 ' the lowest class ' (Class A, fourth below the poverty 

 level !), who had been sent to institutions and trained. 

 She found that 192 (72 per cent.) turned out well ; that 

 44 (16 per cent.) were doubtful ; and that only 29 (less 

 than 11 per cent.) were unsatisfactory, and of these 13 

 were defectives. These figures, which should be checked 

 and multiplied, afford some evidence of the controllability 

 of life. 



We have given in the above paragraphs illustrations 

 of a number of facts : that nurture is important as a 

 condition of normal development, that on its richness in 

 liberating stimuli the degree of development in part 

 depends, that even a slight change in nurture may mean 

 a great deal, that in mammals especially it is not always 

 easy to distinguish what is in the strict sense inherited 

 from what is due to ante-natal nurture, that nurtural 

 effects though not transmissible may be in several ways 

 of indirect racial importance. It has also been pointed 

 out that there are some facts suggesting the theory that 

 peculiarities of nurture may act as variational stimuli 

 -tending to the emergence of the new. 



It would be quite fallacious to argue from any of the 

 illustrations given to man, but perhaps enough has been 

 said to suggest the undesirability of losing faith too 

 utterly in the potency of nurture in shaping the indi- 

 vidual life. Of the danger of arguing from one case to 

 another, an interesting illustration may be found in experi- 

 ments 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 weaken- 

 ing in the power of resistance to deleterious influences. 

 Twenty-eight generations were studied and the evil 



1 Longmans, 1912. 



