CHAPTER V 



THE INHERITANCE OF ACQUIRED CHARACTERS 

 1. SUMMARY OF PRECEDING CHAPTERS 



HEREDITARY resemblance is due to the derivation of 

 offspring from the same stock as the parent, and suc- 

 cessive generations, therefore, are simply periodic 

 expressions of the same continuous stream of germ- 

 plasm. 



Perfect inheritance, or uniformity of generations, 

 does not exist, since variations always occur in suc- 

 cessive generations. It is upon these variations that 

 evolution depends. Without them there would be 

 no change of type and consequently no possibility 

 of evolutionary advance. 



Some variations are fluctuating or continuous in 

 character and may be detected and analyzed by 

 statistical methods, while others are mutations, or 

 discontinuous variations, representing qualitative 

 differences which do not lend themselves readily to 

 statistical analysis. 



Mutations are more common than was formerly 

 believed, and since they are germinal rather than 

 somatic in character, they play an important role 

 in heredity. 



74 



