CHAPTER II 



THEORIES OF HEREDITY 



Students of biology have ranged themselves 

 into hostile camps, controversy between which 

 has at times raged with a severity almost worthy 

 of theologians in the days of bell, book, and 

 candle. On the one side are those that believe 

 in the transmissibility of acquired characteristics, 

 and on the other those that disbelieve in it. 

 Latterly, these parties have been led by Herbert 

 Spencer and August Weismann, the latter a pro- 

 fessor in the University of Freiburg ; Charles 

 Darwin being on the side of Spencer, and Hackel 

 on the side of Weismann. Of these masters of 

 science, the latter has probably the greater repu- 

 tation as an original investigator, while the 

 former is the pre-eminent English philosopher 

 of our time. It is not easy to state in simple 

 terms the exact difference between their theories. 

 They agree as to the fact of heredity, and differ 

 but little in their definitions. They are at vari- 

 ance chiefly in their explanations of the process 

 by which heredity works. Darwin, Spencer, and 



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