20 SEX 



a recent writer who says : " The links that 

 bind a young man in the pride of life with a 

 rutting stag, or a mother and her baby with 

 a she-bear and her cubs, are insignificant com- 

 pared with the differences that divide them. 

 Human conduct, human happiness, and the 

 present and future of the human race are 

 bound up with the differences between man 

 and animals, and not with the resemblances." 

 We should say " with the differences as well 

 as with the resemblances," and we should 

 alter the word insignificant to " of less 

 moment than " ; but the quotation expresses 

 an important protest, against a too simple 

 "biologism," and with this protest we heartily 

 concur. 



Yet our course of action must be not to 

 make 'ess of biology either in enquiry or in 

 use, but of the higher sciences more of psy- 

 chology, ethics, and social science for choice. 



CHAPTER II 



THE EVOLUTION OF SEX 



Ancient origin of sex The case of Volvox Significance 

 of conjugation in the Protozoa Body-cells and germ- 

 cells Advantages of ^exual reproduction Sperm-cells 

 and egg-cells Significance of fertilisation Males and 

 females Testes and ovaries Sex-dimorphism Sex- 

 awareness Physical fondness ^Esthetic attraction 

 Co-operation of the sexes Love. 



IN the volume Evolution in this Library, 

 we have discussed some of the great steps in 

 the history of organisms : the appearance of the 

 relatively simple Protists; the parting of 



