46 HEREDITY AND SELECTION IN SOCIOLOGY 



the soma and of external conditions was rejected. A number 

 of those cases which the defenders of the Lamarckian system 

 had considered as decisive evidence of the hereditary character 

 of acqiiired characters have been explained more satisfactorily 

 by germinal selection. Germinal selection is the necessary 

 corollary to the theory of the continuity of the germ-plasm. 



The elementary particles of the germ-plasm require nourish- 

 ment, and receive it. We must suppose the nutrition of the bio- 

 phors to be effected by means of a fluid circulating between them 

 in the plasm. Biophors, being living units, have consequently 

 the faculty of assimilation and of growth. It follows that the 

 quantity of nutritive fluid which a determinant is capable of 

 obtaining and of assimilating is the factor which regulates the 

 growth and strength of that determinant. The strength of a 

 determinant does not, however, depend entirely on the quality 

 of nourishment available, but also on the assimilating power of 

 that determinant. Primary inequalities in the composition of 

 the determinants are caused by unequal distributions of intra- 

 plasmic nutrition. 



The original condition of this unequal distribution of intra- 

 plasmic nutrition is undoubtedly to be found in the external 

 conditions, such as light, heat, and other environmental in- 

 fluences. Temperature, for instance, can exert an indubitable 

 influence on the nutritive conditions of the germ-plasm. External 

 conditions are by no means homogeneous, and their perturba- 

 tions cause difEerences of individual growth, of collective multi- 

 pKcation, and of chemical composition, among the determinants. 



Even were these differences at the outset confined to but 

 few organisms, amphimixis would not faU to enlarge their circle 

 by the mingling of heterogeneous ids ; and the reduction of the 

 ids to one half their original number, which we observed as the 

 result of the maturation of the elements, effects changes in the 

 composition of the individual germ-plasm. Homogeneous ex- 

 ternal conditions cannot fail to exert different influences on these 



