CHAPTER II 



THE MATERIAL INVESTIGATED. 



List of Structural Characte7^s in Plants and Animals — 

 List of Types in which the inheritance of Colour has 

 been studied — Preliminary Deductions — Dominance 

 and heterozygoiis characters — Mendel's system distin- 

 guished from that of Gallon, 



Heredity following the general rules described In the 

 last chapter has been witnessed in a great diversity of 

 animals and plants. The characters already proved to 

 follow such rules show an equal diversity. The following 

 is a list of some of them. Adequately to represent the facts 

 respecting each of these cases lengthy description w^ould be 

 needed. In regard to several of them occurrences which 

 do not readily fall into line have been recorded. Of these 

 some are probably due to errors of observation or mistakes 

 of various kinds, but a few will doubtless prove to be 

 genuine exceptions to rule and may constitute points of 

 departure for fresh and more extended research. In the 

 outline of the phenomena, w^hlch Is all that this book can 

 profess to offer, it seemed best to restrict as far as possible 

 the enumeration of these details, w^hich can only be 

 thoroughly appreciated by reference to the original papers ; 

 but such annotations as appeared necessary either in elucida- 

 tion of the phenomena or by way of incentive to further 

 work are briefly given with references to the original 

 sources. These annotations will be better understood after 

 the later chapters have been read. 



In the following list when one character is conspicuously 

 dominant it is put first, but in several cases the dominance 

 is imperfect. 



Plants, 



I. Tallness and dwarfness. Peas [Piszim) and Sweet 

 Peas [Lathyrus odoratus). Runner and French Beans 

 (JPhaseolus). 



As regards Peas the facts have been recorded by Mendel (195), ; 

 Tschermak (269, 270, &c.), R.E.C. * (20). When varieties differing \ 



* R.E.C. stands throughout for Reports to the Evolution Committee of ' 

 the Royal Society, giving an account of the experiments of W. Bateson, . 

 E. R. Saunders and R. C. Punnett. Other contributors to these Reports 

 are mentioned by name. 



