20 8 PIONEERS OF EVOLUTION PART 



lower life-forms. As stated on p. 172, Mr. Herbert 

 Spencer traces the gradual evolution of consciousness 

 from * the blurred, indeterminate feeling which re- 

 sponds 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, 

 digests 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 

 appear ; the development of function and organ 

 going on simultaneously. 



Speaking broadly, the functions of living things 

 are threefold : they feed ; they reproduce ; they 

 respond to their 'environment,' and it is this last- 

 named function communication with surroundings 

 which is the special work of the nervous system. 

 It was an old Greek maxim that ' a man may once 

 say a thing as he would have said it : he cannot say 

 it twice.' This is the warrant for transferring a few 

 sentences on the origin of the nerves from my Story 

 of Creation. They are but a meagre summary of Mr. 

 Spencer's long, but luminous exposition of the subject. 



* As every part of an organism is made up of cells, 

 and as the functions govern the form of the cells, the 

 origin of nerves must be due to a modification in cell 

 shape and arrangement, whereby certain tracts or 

 fibres of communication between the body and its 

 surroundings are established/ 



