CH. VIII] PFLUGER'S EXPERIMENTS 89 



then of equal value and are composed of equivalent molecular 

 rows. Gravity alone has determined which of all possible 

 meridians shall be the controlling one." 



He adds : " I imagine that the fertilized egg bears no more 

 relation to the later organization of the animal than the snow- 

 flakes bear to the size and structure of the glacier that develops 

 from them. From a germ there always arises the same struct- 

 ure because the external circumstances remain the same. The 

 glacier that develops out of the snowflakes has always the same 

 form, so long as the external conditions are unchanged." 



