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 gencrally 
accepted up to the middle of the nineteenth century, but the 
reaction against it started by Galton and others has assumed 
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. More 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 (1822-1884) (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 which bids fair to be one 
of the great biological discoveries of the nineteenth century. 
He published his papers in 1866 and 1867, but since the minds 
of naturalists at that time were very much occupied with the 
