224 



PIONEERS OF EVOLUTION. 



with these conditions, they have yet to be discov- 

 ered. 



When the argument against the evolutionist is 

 drawn from human testimony, he does not dispute 

 the existence of the belief in a soul and in all the 

 accompanying apparatus of the supernatural; but he 

 calls in the anthropologist to explain how these arose 

 in the barbaric mind. 



Meanwhile, let us summarize the evidence which 

 points to the psychical unity between man and the 

 lower life-forms. As stated on p. 187, Mr. Herbert 

 Spencer traces the gradual evolution of conscious- 

 ness from " the blurred, indeterminate feeling which 

 responds to a single nerve pulsation or shock." 

 There is no trace of a nervous system in the simplest 

 organisms, but this counts for little, because there 

 are also no traces of a mouth, or a stomach, or limbs. 

 In these seemingly structureless creatures every part 

 does everything. The amoeba eats and drinks, di- 

 gests and excretes, manifests "irritability," that is, 

 responds to the various stimuli of its surroundings, 

 and multiplies, without possessing special organs for 

 these various functions. Division of labour arises at 

 a slightly higher stage, when rudimentary organs ap- 

 pear; the development of function and organ going 

 on simultaneously. 



Speaking broadly, the functions of living things 

 are threefold: they feed; they reproduce; they re- 

 spond to their " environment," and it is this last- 

 named function communication with surroundings 



