238 REPRODUCTION, PUBERTY AND LONGEVITY. 



maels." Although these people live in a climate where the average 

 age of puberty is between 14 and 15 years, many of the girls bear 

 children before these ages and sometimes are mothers at 12. Parents 

 who necessarily work hard are less likely to indulge in sexual ex- 

 cesses than those who live in luxury and ease, a fact that readily 

 accounts for the difference in age of puberty between the upper 

 and lower classes of Paris and the difference between city and 

 country. This is a better explanation than assuming that the dif- 

 ference is caused by the food and mode of life of. the children 

 themselves, because some of the poorest and most illy nourished are 

 notoriously licentious and their children come earliest to puberty. 

 Besides the Jukes and the Ishmaels we have an example in the 

 Eskimos, who are low in the scale of intelligence, who idle in their 

 huts except when forced to seek food, who are immoral in their 

 sexual relations, and who come to puberty at an early age in defiance 

 of the effects of temperature and quality of food. I have before 

 pointed out that the lower classes produce children at a very early 

 age, and Darwin speaks of most savages as being "utterly licen- 

 tious." 3 



We may therefore conclude that early puberty is a case of use- 

 inheritance arising from sexual intensity and excess in parents, 

 and that it has its orgin in early reproduction. 



EARLY REPRODUCTION AND LONGEVITY. 



Early reproduction and early puberty not only lead to low 

 mentality and degeneracy, but to early decay and early death. 

 Lankester gives 4 the following table of expectancy of life : 



(3) Descent of Man, Vol. II, p. 366. 



(4) Comparative Longevity, p. 118. 



