120 THE EVOLUTION THEORY 



germinal fluctuations of nutrition, this is transmitted to the 

 descendants just as well as the normally developed organ, and in 

 the course of generations will be inherited by a greater and greater 

 number of individuals, and must ultimately be inherited by all in 

 some degree or other. The olyection has been urged from many 

 sides that variations upwards would be quite as likely to arise as 

 those downwards, but this is an error. Even if, at the beginning, 

 the minus-variations were rarer than the plus-variations, in the 

 course of generations the minus ones would preponderate because 

 ascending variations of disused organs are not indifferent for the 

 organism but injurious to it. Perhaps an increase in the size of the 

 organ itself would do no harm, but in that of its determinant 

 it certainly would, because an ascending determinant requires more 

 nourishment than previousl}^, and withdraws it from its surroundings, 

 and thus from the determinants in its immediate neighljourhood ; 

 but these are those of functioning and indispensable parts. Individuals 

 in whose germ-plasm the determinants of disused organs ascend, and 

 thereby depress the determinants of organs which are still active, 

 are subject to personal selection, and are eliminated. There thus 

 remain only those with descending determinants ; in other words, 

 the chance of variants in the direction of weakness in useless deter- 

 minants far outweighs that of variants in the direction of increased 

 strength ; the latter will soon cease to occur at all, for as soon 

 as a determinant has fallen a little below its normal level, it finds 

 itself upon an inclined plane, along which it glides very slowly 

 but steadily downwards. Tliis might be disputed if it could be 

 maintained that, at every stage of the descent, a change of direction was 

 possible. But this probably takes place rarely and only in the case 

 of individual ids, and will therefore not be permanent because 

 in general the stronger neighbour determinants will possess them- 

 selves of the superfluous nourishment, and a lasting ascent will thus 

 be impossiljle to the weakened determinant. This is precisely what 

 I have called Germinal Selection. The determinant whose assimilat- 

 ing power is weakened by ever so little is continually being robbed 

 by its neighbours of a part of the nourishment which flows towards 

 it, and must consequently become further weakened. As ncj more 

 help will be given to it by natural selection, since the organ is no 

 longer of any value to the species, the better among the weakened 

 determinants of X are never selected out, and they must gradually give 

 way in the struggle with the neighbouring determinants which are 

 necessary to the species, becoming graduall}^ weaker and ultimately 

 disappearing. 



