120 UNIVERSAL EVOLUTION 



system, in control of their mechanism, in like simplicity. 

 The complexity of the nervous system corresponds with 

 that of the mechanism of the organism. This corre- 

 spondence produces a uniform result, and that result 

 is always produced in only one manner. This is called 

 instinct. Now, as soon as there came into being an 

 animal with the manifest power of another choice as 

 to the mode of responding to his environment, possessed 

 of the additional tool, or the ability to make a tool to 

 aid his natural tools, or who could make a fire, and thus 

 work in a way before unknown, that variety of animal, 

 we now call man, and his ability to choose his mode 

 of acting on matter or environment, is called intelli- 

 gence. Investigation discovered that this man and this 

 intelligence possessed a more complicated nervous 

 system than the animals whose work is instinct; but 

 that the complexity of his nervous system is made up 

 of the expansion by growth of the same nervous matter 

 of the instinctive animals, and not matter of a different 

 kind. 



It is a well known fact, that in the decline of vitality 

 accompanying old age of man, the functions last devel- 

 oped in life, are the earliest lost. The term "second 

 childhood" is the popular recognition of a profound 

 psychological truth. The highest intellectual functions 

 soonest fade, while the instincts and emotions, which 

 existed almost at birth, remain to the latest breath. 

 Those phenomena, which accompany normal senile decay 

 in man, are strikingly similar to those which the vivi- 

 sectionist is able to produce with his knife. 



Remove the cerebral hemisphere of a pigeon, and it 

 returns to a condition closely resembling that of the 

 newly hatched bird, it will swallow food placed in its 

 mouth, and if you turn it on its back it will regain its 



