GERMINAL SELECTION. 43 



a disadvantage as compared with the determinants 

 of their environment in the germinal tenement, because 

 no assistance is offered to them by personal selection 

 after they have once been weakened by a decrease of 

 the passive nutrient influx. Nor is the degeneration 

 stopped by the uninterrupted crossing of individuals 

 in sexual propagation, but only slightly retarded. The 

 number of individuals with weaker determinants must, 

 despite this fact, go on increasing from generation to 

 generation, so that soon every determinant that still 

 happens to be endowed with exceptional vigor will be 

 confronted by a decided overplus of weaker determi- 

 nants, and by continued crossing therefore will become 

 more and more impoverished. Panmixia is the indis- 

 pensable precondition of the whole process ; for owing 

 to the fact that persons with weak determinants are 

 just as capable of life as those with strong, owing to 

 the fact that they cannot now, as formerly, when the 

 organ was still useful, be removed by personal selec- 

 tion, solely by this means is a further weakening ef- 

 fected in the following generations in short, only 

 by this means are the determinants of the useless organ 

 brought upon the inclined plane, down which they 

 are destined slowly but incessantly to slide towards 

 their completed extinction. 



The foregoing explanation will be probably accepted 

 as satisfactory in a purely formal regard, but it will be 

 objected that, even granting this, it has not yet been 

 proved to be the correct one. In answer I can of 

 course adduce nothing except that it is at present the 

 only one that can be given. It may be that the actual 

 state of things in nature is different, but if it can be 

 shown that a self-direction of variation merely from 

 the need of it is at all conceivable by mechanical means, 



