40 HEREDITY AKD SELECTION IN SOCIOLOGY 



the successive embryonic ceUs that the crooked or the aquihne nose was 

 bound to'SbeJthe ultimate product of their co-operative development. 

 Thus it is with the whole organism : the whole of the nervous system, the 

 vascular system, the glands, the muscles, the digestive apparatus, the 

 reproductive organs, all are determined by the intervention of successive 

 determinant complexes during the embryonic development. The modifica- 

 tion of the organ, or system of organs, through the intervention of one kind 

 of determinants, to the exclusion, or partial exclusion, of the rest, is a 

 modification due, in the ultimate instance, we have seen, to the preponder- 

 ance of the specific excitation pertaining to those particular determinants. 



