76 HEREDITY AND EVOLUTION IN PLANTS 



65. Relation of Weismannism to Mendelism. It will 

 readily be recognized that the "determinants" of Weis- 

 mann are the "factors" of Mendelian nomenclature. 

 Morever, it follows logically from Weismann's theory 

 that acquired characters are not inherited, an inference 

 that agrees with observation and experiment. Nageli, 

 director of the botanic garden in Munich, transplanted 

 specimens of Hawkweed (Hieraceum) from the high Alps 

 to the lower altitude and changed climate of his garden, 

 and these plants began to manifest new characters which 

 reappeared in successive generations for more than a 

 decade. This looked like the inheritance of acquired 

 characters, but when the plants were subsequently taken 

 back to the high Alps, they failed to manifest the charac- 

 ters expressed in the botanic garden, reverting to their 

 former alpine characteristics. Thus it is seen that the 

 reappearance of the new characters in successive genera- 

 tions in the botanic garden was not due to inheritance of 

 these acquired characters, but to the continuity of the 

 new environment. The inheritance had not been altered 

 though the expression of it had. This is in agreement with 

 what we should expect from the definition of inheritance 

 given on page 50. l 



66. Eugenics. Students of biology have been quick 

 to recognize the fact that, if we correctly understand the 

 laws of heredity, we are in a position to apply them, not 

 only to plants and the lower animals, but to mankind. 

 The application of the laws of heredity in a way to produce 

 a healthier and more efficient race of men constitutes the 

 practice of eugenics. 2 The underlying principles of eugenics 



1 See also pages 48 and 66-67. 



* The word eugenics is from two Greek words meaning well born. 



