QUESTION OF PHYSICAL DEGENERATION 277 



has steadily declined from 36*3 in 1876 to 29*7 in 1896. In 

 1877 there was a decline in the marriage-rate, and since then 

 there has been but little recovery. For the period 1867-1876 

 the average annual rate was 16*65 to loo persons living, from 

 1877-1886 only 15*01. Since which date there has been a 

 slight rise, the average from 1887-1896 being 15*09. Thus 

 the reduced birth-rate is very largely due to the reduced 

 marriage-rate, but it is known that, in addition to this, a cause 

 of decline that has long been at work in France has begun 

 to tell in England also, viz., artificial restriction. 1 Now this 

 has, 1 believe, an important bearing on the question now under 

 discussion, the tendency of civilised man to degenerate physically. 

 The reader will remember that Professor Karl Pearson has 

 shown that twenty-five per cent, of the marriages produce quite 

 fifty per cent, of the next generation. It is beyond dispute 

 that the fertility of the mothers of large families is correlated 

 with general vigour. In the absence of restrictions, therefore, 

 the great majority of the next generation will spring from these 

 vigorous mothers. But supposing that, for the reason stated, 

 no family exceeded four, then a far smaller proportion of the 

 next generation would be born from mothers of great fertility 

 and correlated vigour. Thus a decline in the birth-rate even 

 though due to artificial causes must lead to a decline in the 

 vigour of the race. 



Further than this, if fertility is hereditary (and there is reason 

 to believe that it is 2 ), the artificial limitation of the number 



1 The report of the Registrar-General for 1898 leaves little doubt on the subject, 

 for the last three years for which the figures are published (1896-1898) show a 

 continuous rise in the marriage-rate and yet the birth-rate has continued to decline. 



2 See Prof. Karl Pearson's paper Proc. Royal Society, vol. Ixiv. p. 163. He 

 decides that fertility is undoubtedly inherited from mother to daughter, but that 

 thfs is largely screened by other factors. The more stringently these factors are 

 removed, " the more the regression of daughter on mother moves up towards the 

 value required by the law of ancestral heredity." , 



Mr Howard Collins in a letter in Nature, Nov. 3rd, 1898, brought to light some 

 very remarkable facts that seemed to show that in the most wealthy classes fertility 

 was quite independent of heredity. However, evidence drawn from so artificial 

 a stratum is necessarily rather untrustworthy, and we may accept Prof. Karl 

 Pearson's decision. Heredity is a factor but it is not the only one. Environment 

 and age at marriage count for a great deal. 





