135 



APPENDIX I 



HISTORICAL SUMMARY OF THEORIES 

 OF HEREDITY 



In the foregoing pages, Heredity has been regarded 

 as the relation between parents and offspring in 

 respect of their bodily characters, and it has been 

 shown that this relation has been brought about in 

 some way by the germ-cells, but very little has been 

 said about the mechanism by which this is effected. 

 This side of the question is very largely speculative, 

 and in order to keep speculation to some extent 

 apart from facts, an account of theories of hereditary 

 transmission, and of recent work on the supposed 

 material basis of hereditary characters, has been 

 postponed to appendices, which the reader who seeks 

 for facts and well-founded deductions alone, may 

 omit at will. First, a summary of the chief theories 

 of heredity will be given, and then a short account of 

 recent work on the subject. 



In the introduction it was pointed out how closely 

 related are our ideas of Heredity and Variation with 



