PHYSICAL EVOLUTION 231 



Here I may recall what I have said before, that strictly speak- 

 ing all strength is relative to conditions ; hence, if the conditions 

 soften more rapidly than physique deteriorates, the net result is 

 that there is an increased amount of physical strength available 

 in the nation. But in estimating the value of this increase, we 

 must not lose sight of an important distinction : vigour in indi- 

 viduals is not the same thing as race vigour. It may be due 

 to an almost ideally good environment. Race vigour, on the Race 

 other hand, is the product of hard conditions: when an ind 

 vidual sprung from a race thus evolved is transplanted to a in the 

 softer environment, then personal vigour is most likely to make in 

 its appearance since it consists in an ample margin of superiority 

 to conditions. In places and in social strata in which the death- 

 rate is high we may consider that race vigour is being maintained 

 by the elimination of the weakly ; where it is low the strength 

 of the existing generation is being developed and made the most 

 of a process that is fraught with danger, since it involves the 

 survival of many persons of poor physique, and as a consequence, 

 I believe, unless the process is checked, eventual race-deteriora- 

 tion. It is, in fact, a draught upon capital. That there must 

 be some decline seems to follow as a necessary consequence 

 from the facts. To take an extreme case : suppose that all 

 elimination ceased, and that all of this generation left descend- 

 ants instead of only the more vigorous 50 or 5 2 P er cent., 

 English physique would clearly drop below its present level. 

 But the question is whether having dropped so far, it would 

 drop any further. Some biologists maintain that the characters 

 a race has once gained belong to it in perpetuity, unless they 

 are removed by Natural Selection. They cannot be lost, it is 

 maintained, merely because they are no longer specially selected ; 

 if elimination for a particular defect ceases there will be a decline 

 from the survival mean to the birth mean, but no further. On 

 the other hand, Weismann has contended that there will be a 

 process of retrogression or degeneration which will continue 

 as long as the environment continues to become less and less 

 exacting. This question I am going to discuss in the next 

 chapter. 



