No. 582] SIGNIFICANCE OF INTERNAL CONDITIONS 323 



parthenogenesis, the modification of mental and moral 

 traits, and the extent of regeneration of lost parts. 

 When arranged in the order of their position in the 

 taxonomic scale, organisms show a steadily decreasing 

 response, with reference to these phenomena, to changes 

 in the environment. Woods does not indicate, except in 

 very general terms, the physiological mechanisms in- 

 volved in bringing about this diminishing effect of the 

 environment. Some years earlier Donaldson 6 had called 

 attention to the general lack of influence of formal edu- 

 cational training upon the course of later life of talented 

 individuals. 



Julian Huxley 7 in his discussion of the individual in 

 the animal kingdom, points out that the individual 

 acquires an increasing independence of the environment, 

 or that the environment has a diminishing effect. Hux- 

 ley assigns mere increase in size and the increasing com- 

 plexity and efficiency of the nervous system as two of the 

 factors involved in the attainment of the freedom from 

 mere accidents. 



Mathews s has pointed out more specifically some of the- 

 various internal mechanisms which are involved in the 

 acquisition of independence of the environment on the 

 part of the higher animals. These are, according to him,. 

 (1) the heat-regulating mechanism, (2) the mechanism, 

 of immunity, (3) the mechanism for rendering animals 

 independent of external conditions of moisture, (4) the 

 mechanism which renders them independent of barometric 

 pressure, (5) the mechanisms for reproduction and car- 

 ing for the young, (6) the alimentary mechanism, and (7) ; 

 the nervous system. 



Henderson 9 has shown that the environment is an ex- 

 ternal thing in which certain physico-chemical conditions 

 are kept relatively constant, while others may vary 



