258 Heredity and Eugenics 



as is known, these are superficial relations and are not of 

 themselves concerned in establishing the fundamental 

 symmetries and activities which seem to be in the main 

 conditioned and controlled by the colloidal matrix which 

 underlies all visible structure. The only safe statement which 

 can be made at present is an acknowledgment of our ignor- 

 ance of what the changes are in the germ cell which are 

 productive of new arrangements in form and symmetry. 

 However, it is experimentally proven these fundamental 

 relations can be altered by one process or another, thus 

 giving methods of inducing changes and of discovering 

 what changes are possible, both as regards the limits of 

 change, direction, rate, etc., and this knowledge may be 

 of great practical value even though the underlying physico- 

 chemical operations are still undetermined and possibly 

 unknowable. 



In the modification of characteristics which are directly 

 conditioned by chemical activities, as, for example, color, 

 there seems a greater possibility of attaining at least a 

 general idea of the processes involved in the germ cells in 

 producing permanent changes. Pigments, throughout the 

 organic world, are pretty generally the result of metabolic 

 processes and are probably in most instances the result of 

 the oxidation of various cleavage products which have 

 themselves been formed by the breaking down of more com- 

 plex substances within the cell. Many of these chromogen 

 substances are possibly waste materials in the organism, 

 which perhaps could not be further utilized in the economy 

 of the animal, so this method arose of converting them into 

 more or less harmless substances and depositing them in 

 places where they would be least inconvenient to the 

 organism. This old conception of the character of coloration 



