CONTENTS. 1 1 



CHAPTER XIV. 



PAGE 



Lower Animals 217 



Basis of comparison — Size and activity of different 

 animals — Anthropoid apes: The orang-utan and chim- 

 panzee — Horses : English thoroughbreds — American trotters 

 — Testimony of horse breeders — Breeding from immature 

 animals — The fastest trotters in the world — The greatest 

 sires of speed — Transmission by sex in horses — Relation 

 of age and training in sires — Reproduction earlier in 

 common than in blooded horses — Cattle: Early breeding 

 — Birth-ranks of famous bulls — Average for ordinary 

 cattle — Dogs and sheep — Rabbits and squirrels — Hibernat- 

 ing squirrels — The beaver — Seals and deer — The elephant 

 and hippopotamus — Guinea pigs — White mice — Common 

 fowl — Crows — Parrots — Bee — Moth — Coccus — Ant. 



CHAPTER XV. 

 Reproduction, Puberty and Longevity 232 



Lamarck's laws and their proof — The factors of use, 

 how combined — Diagram of animals by the factor of age — 

 Proportion of life during which developing activity con- 

 tinues — Relative variations of time and activity — Time a 

 stimulus for mental activity — The rise of races — Time 

 between generations increased by delay of puberty — 

 Puberty affected by climate and mode of life — Age of 

 puberty at different places — Variations by latitude — 

 Adolescence a period of acute sexuality — Early puberty 

 caused by congenital acute sexuality — Degenerate and 

 luxurious classes come early to puberty — Early reproduc- 

 tion and length of life — Length of life of different classes 

 — Longevity and mental aptitudes — Relation of birth- 

 rank to longevity — Selection eliminated — Longevity of 

 different sons of the same family — Longevity and birth- 

 ranks of brothers and sisters — Birtht-ranks and ex- 



