CHAPTER XIV 



HEREDITY AND GERMINAL CONTINUITY- 

 MENDEL, GALTON, WEISMANN 



It is a matter of common observation that in the living 

 world like tends to produce like. The offspring of plants, 

 as well as of animals, resembles the parent, and among all 

 organisms endowed with mind, the mental as well as the 

 physical qualities are inherited. This is a simple statement 

 of the fact of heredity, but the scientific study of inheritance 

 involves deep-seated biological questions that emerged late 

 in the nineteenth century, and the subject is still in its 

 infancy. 



In investigating this question, we need first, if possible, 

 to locate the bearers of hereditary qualities within the physical 

 substance that connects one generation with the next; then, 

 to study their behavior during the transmission of life in order 

 to account for the inheritance of both maternal and paternal 

 qualities; and, lastly, to determine whether or not transiently 

 acquired characteristics are inherited. 



Hereditary Qualities in the Germinal Elements. — When 

 we take into consideration the fact established for all animals 

 and plants (setting aside cases of budding and the division 

 of unicellular organisms), that the only substance that passes 

 from one generation to another is the egg and the sperm in 

 animals, and their representatives in plants, we see that the 

 first question is narrowed to these bodies. If all hereditary 

 qualities are carried in the egg and the sperm — as it seems 

 they must be — then it follows that these germinal elements, 



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