314 BIOLOGY AND ITS MAKERS 



to the development of particular parts of the embryo. The 

 removal of any one of these pre-localized areas prevents the 

 development of the part with which it is genetically related. 

 Researches of this kind, necessitating great ingenuity in 

 method and great talents in the observers, are widening the 

 field of observation upon the phenomena of heredity. 



The Inheritance of Acquired Characteristics. — The belief 

 in the inheritance of acquired characteristics was generallv 

 accepted up to the middle of the nineteenth century, but the 

 reaction against it started by Galton and others has assumicd 

 great proportions. Discussions in this line have been carried 

 on extensively, and frequently in the spirit of great partizan- 

 ship. These discussions cluster very much about the name 

 and the work of Weismann, the man who has consistently 

 stood against the idea of acquired characteristics. IMore in 

 reference to this phase of the question is given in the chapter 

 dealing with Weismann's theory of evolution (see p. 398). 

 Wherever the truth may lie, the discussions regarding the 

 inheritance of acquired characteristics provoked by Weis- 

 mann's theoretical considerations, have resulted in stimulat- 

 ing experiment and research, and have, therefore, been 

 beneficial to the advance of science. 



The Application of Statistical Methods and Experiments to 

 the Ideas of Heredity. Mendel. — This feature of investigating 

 questions of heredity is of growing importance. The first 

 to complete experiments and to investigate heredity to any 

 purpose was the Austrian monk Mendel (182 2-1 884) (Fig. 95), 

 the abbot of a monastery at Briinn. In his garden he made 

 many experiments upon the inheritance, particularly in peas, 

 of color and of form; and through these experiments he 

 demonstrated a law of inheritance wliich bids fair to be one 

 of the great biological discoveries of the nineteenth century. 

 He pubhshed his papers in 1866 and 1867, but since the minds 

 of naturalists at that time were very much occupied with the 



