CHAPTER II 



PHENOMENA OF INHERITANCE 



A. OBSERVATIONS ON INHERITANCE 



The observations of men for ages past have established the fact 

 that in general "like produces like," and that, in spite of many 

 exceptions, children are in their main characteristics like their 

 parents. And yet offspring are never exactly like their parents, 

 and this has led to the saying that "like does not produce like 

 but only somewhat like." What is meant is that there are gen- 

 eral resemblances but particular differences between parents and 

 offspring. 



INDIVIDUALS AND THEIR CHARACTERS 



In considering organic individuals one may think of them as 

 wholes or as composed of parts, as indivisible unities or as consti- 

 tuent characters; either aspect is a true one and yet neither is 

 complete in itself. Formerly in discussions on heredity the 

 individual was regarded in its entirety and when all hereditary 

 resemblances and differences were averaged it was said that one 

 child resembled the father, another child the mother. This 

 method of lumping together and averaging resemblances and dif- 

 ferences led to endless confusion. In heredity no less than 

 in anatomy it is necessary to deal with the constituents of organ- 

 isms; in short, the organism must be analyzed and each part 

 studied by itself. 



Method of Gallon and Mendel. Francis Galton was one of the 



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