INFLUENCE OF HOMODYNAMIC DETERMINANTS 161 



ids of the germ-plasm. Among the difEerent determinant 

 complexes which proceed from the heterogeneous ids, the 

 complex which will have the greatest chance of determining the 

 nature of a germ-cell will be that represented by the greatest 

 number of hemodynamic determinants. Homodjmamic deter- 

 minants, whether inherited from one of the parents or from both 

 of them, will always compound their respective forces, whereas 

 the heterodynamic determinants can, at most, produce a diagonal 

 result ; as a matter of fact, it must often happen that they 

 inhibit one another, and, by reason of their opposition, mutually 

 neutraHse their influence. When a small minority of homo- 

 dynamic determinants is opposed to an overwhelming majority 

 of heterodynamic ones, the former will necessarily be rendered 

 powerless as far as their effect on the development is concerned ; 

 and if a group, or groups, of heterodynamic determinants should 

 acquire renewed strength as a result of amphimixis, this small 

 minority may be eliminated entirely from the germ-plasm. 

 Nevertheless, hemodynamic determinants are by their nature 

 more likely to acquire an influence in the determining of the 

 germ-plasm than heterodynamic ones ; and a large minority of 

 such homodynamic determinants may succeed in determining 

 the nature of the germ-cell when the majority of determinants 

 are heterodjniamic, and mutually inhibit one another. 



As a rule, neither the father nor the mother has a prepon- 

 derating hereditary influence. Nevertheless, oSspring do not 

 represent an average, or a " middle line," between their parents ; 

 for, if this were the case, all the children of a pair would be 

 similar. As a matter of fact, the child, in one case, resembles 

 its father, in another its mother, in a third case it resembles 

 more or less closely one of its forefathers, and occasionally it 

 is what is called a monstrosity — that is to say, it departs more 

 or less completely from the morphological type of the species. 

 The differences between the offspring of the same pair are 

 due to the reduction phenomena which we have noticed, and 



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