DIMINISHING ENVIRONMENTAL INFLUENCE 335 



matter of course. Its only interest for us lies in the fact that most 

 alterations in the surroundings that are brought to bear upon hu- 

 man beings are probably not very great in actual differences. They 

 are at least not great in comparison with the experiments of the 

 botanist and zoologist. (2) Environmental influence diminishes with 

 increased phylogenetic rank. (3) Environmental influence diminishes 

 with the evolutionary rank of the tissue affected. (4) Environmental 

 influence diminishes in proportion to the age of the tissue affected. 

 The contents of this paper have been chiefly brought forward to support 

 these second, third and fourth laws. Artificial modification then ap- 

 pears to be easiest upon tissues that are either young or simple, or in 

 a condition of cell subdivision and growth. It must be remembered 

 that the brain-cells, even of a child, are, of all tissues, farthest removed 

 from any of these primordial states. The cells of the brain ceased 

 subdivision long before birth. Therefore, a priori, we must expect 

 relatively little modification of brain function. We next have to 

 consider the question of the possibility of escape on the part of the 

 organism from a novel and perhaps unwelcome environment into its 

 natural one again. (5) Environmental influence diminishes with the 

 organism's power of choice. This may be the chief reason why 

 human beings, who of all creatures have the greatest power to choose 

 the surroundings congenial to their special needs and natures, are so 

 little affected by outward conditions. The occasional able, ambitious 

 and determined member of an obscure or degenerate family can get 

 free from his uncongenial associates. So can the weak or lazy or 

 vicious (even if a black sheep from the finest fold) easily find his 

 natural haunts. 



In ps} r chological matters we are dealing with a totally different 

 class of cases from the zoological experiments referred to in this paper. 

 It is a point often forgotten, yet one that should be constantly born 

 in mind, that there are these two kinds of environment from the 

 standpoint of an organism. There are surroundings from which there 

 is no escape, 'let the creature try his best, and there are also environ- 

 ments from which escape is possible if the inheritant desires impel it. 

 All the modifications on lower animals alluded to in this article are 

 of the first kind, or have been brought about by imposed conditions 

 from which there was no escape. Psychological environment can 

 scarcely be placed in the same category. Therefore the inference is that 

 not only is the brain little influenced by surroundings owing to its high 



steam, which is the essential thing. The purchasing agent pays the highest 

 prices for the very best machine because he knows that having got his best 

 machine he can easily get his fuel and his water. He expects to get these. 

 These form the expected environment which may differ some in quality and 

 effect, but after all, from the practical standpoint, the essential thing is the 

 quality of the machine. It is just so with the human mind. Nature is the 

 great decider because nurture is expected. 



