106 FROM AN EASY CHAIR 



not subjected after birth to any treatment or conditions 

 differing from those common to all of them is a quality 

 of living things which must be distinguished altogether 

 from the power of the individual itself, though not born 

 with qualities differing from those of its brothers and 

 sisters, to vary or change in some respects as compared 

 with other individuals when it is specially fed or ex- 

 posed to special treatment. The first is change, or 

 variation, of the " stirps," or germ plasm ; the second is 

 change, or variation, of the transient body of the indivi- 

 dual. The first is indefinite and may be of almost any kind 

 or form ; once it has appeared, it is a permanent possession 

 of the race descended from its owner. The second is 

 definite and a direct reaction to the environment. Such 

 an individually induced or stimulated change is often 

 called an " acquired character." It does not affect the 

 stirps, the inner reproductive germs, and cannot be 

 handed on by inheritance to a new generation. 



What happens, then, when there is a cessation of 

 selection? All sorts of birth-variations appear and 

 grow up. The fine adjustment of form maintained by 

 natural selection carried on unceasingly no longer 

 obtains. The characteristics of the race become less 

 emphasised. All sorts of birth-variations have an equal 

 chance, and the tendency must be for those charac- 

 teristics which have most recently been established and 

 maintained by severe selection to dwindle and then to 

 disappear altogether. The majority of birth-variations 

 will when selection is prevented always tend to 

 present a lessened, rather than an increased, develop- 

 ment of any one characteristic the excelling minority 

 will no longer be selected, but all will have an equal 

 chance in mating and reproducing. Hence, bit by 

 bit, all salient features, all the characteristics of the 

 race previously maintained by selection, will, as a 

 result of survival of all variations and general cross- 

 ing and interbreeding dwindle and disappear. It is 



