200 DARWINISM TO-DAY. 



of the truth of the theory. A few of these objections 6 may 

 be briefly stated. 



According to the theory there should be plainly exhibited 

 in the variation of any species, decided tendencies in certain 

 Objections to specific directions. In all species, in all indi- 

 mtoafselJcT" viduals, the struggle of the determinants must 

 tion. result in the suppression or reduction of some, 



the extra-development of others. Thus variation should 

 not reveal itself according to the law of error, that is, should 

 not be distributed normally about a mean or mode. But 

 that is exactly the condition of variation in a majority of 

 those cases in which the variation of one or more organs 

 in any species has been statistically studied. The plotted 

 curve of any particular variation of this type is a symmetri- 

 cal curve nearly coincident with the theoretical one express- 

 ing the law of error for the same case. 



The constancy of species is just as marked and actual a 

 condition as the condition of slight fluctuating variations 

 inside the species. This constancy is steadfast for con- 

 siderable time-periods. But with such an active orthogene- 

 sis as the theory of germinal selection provides, there could 

 be no such steadfast constancy. Weismann himself recog- 

 nised the weight of this objection to the theory, and speaks 

 of an attribute of "self-correction" pertaining to the germ- 

 plasm, which shall regulate or check too rapid an ortho- 

 genetic development. 



The actual change of the competitive determinants due 

 to their obtaining an over or under supply of food should 

 be one simply quantitative in degree; such germinal selec- 

 tion could thus lead to the change in size and strength of 

 organs already present in the species, but could offer no 

 explanation of qualitative changes, i. e., the appearance of 

 new kinds of structures. Moreover, even in cases of purely 

 quantitative change, such familiar cases as the persistence 

 through long time-periods of small, rudimentary organs, 



