PROCEEDINQS 



OF THE 



WASHINGTON ACADEMY OF SCIENCES 

 Vol. IX, pp. 189-240. July 31, 1907. 



MENDELISM AND OTHER METHODS OF 

 DESCENT.^ 



By O. F. Cook. 



SYNOPSIS 



Introduction i°9 



The nature of experiments in descent '9' 



Parent organisms produce parent gametes 192 



Parent gametes produce conjugate organisms 192 



Conjugate and exjugate reproduction i93 



Conjugates produce perjugates ^95 



Summary of the five elements of descent i97 



Mendelism as a method of descent ^9° 



Primary methods of descent ^9° 



Synopsis of methods of descent ^99 



Diagram of methods of descent 216 



Position of Mendelism as a method of descent 218 



Mendelian " principles " not demonstrated 218 



Mendelian inheritance of mutations 220 



Problems of expression and transmission 224 



Relation of Mendelism to normal diversity of descent... 230 



Evolutionary implications of Mendelism 232 



Conclusions 230 



All students of Mendelism must be tha^nkful to Professor 

 Davenport for the extensive and very interesting summary of 

 the facts which his experiments have brought to light, and we 

 are very fortunate in this opportunity of having them illustrated 



1 An outline of this paper was presented in a discussion of Professor Daven- 

 port's lecture on " Heredity and Mendel's Lavir," before a meeting of the Wash- 

 ington Academy of Sciences, on February 26, 1907. Considerable amplification 

 has been found desirable in order to carry out more fully the plan of a definite 

 comparison of Mendelism with other methods of descent. 



Proc. Wash. Acad. Sci., July, 1907, 1S9 



