46 THE PHYSICAL KINSHIP 



These facts are unmistakable. There is a reason 

 for everything, and there is a reason for these trans- 

 formations through which each generation of living 

 beings journeys. The individual passes through 

 them because the species to which he belongs has 

 passed through them. They represent ancestral 

 wanderings. As if to emphasise the kinship of all 

 of life's forms and to render incontrovertible the 

 fact of universal evolution, Nature compels every 

 individual to commence existence at the same 

 place, and to recapitulate in his individual evolu- 

 tion the phylogenetic journeyings of his species. 



4. That existing forms of life have been evolved 

 from other forms, and that these ancestral forms 

 have been different from those derived from them, 

 is shown by the occasional appearance of ante- 

 cedent and abandoned types of structure among 

 the offspring of existing species. Occasionally a 

 human child is born strangely unlike its parents, 

 but bearing an unmistakable resemblance in looks 

 and disposition to his great-grandfather or some 

 other remote ancestor. This is atavism, that 

 tendency to revert to ancestral types which is pre- 

 valent among all animals. We may think of it 

 figuratively as a flash of indecision when Nature 

 hesitates for a moment whether to adopt a new 

 form of structure or cling to the old and tried. 

 Horses and mules are sometimes born with three 

 toes on each foot, and zebra-like stripes on their 

 legs and shoulders ; and domestic pigeons, such as 

 are naturally black, red, or mottled, occasionally 

 produce offspring with blue plumage and two black 



