146 THE POPULAR SCIENCE MONTHLY. 



nificance of the merely animal differences between the sexes, as com- 

 pared with their intellectual and moral influence, it is none the less 

 true that the origin of the latter is to be found in the former ; in the 

 same manner to use a humble illustration that the origin of the 

 self-denying, disinterested devotion of a dog to his master is to be 

 found in that self -negation which is necessary in order that a herd of 

 wolves may act in concert under a leader, for the general good. 



In order 'to trace the origin and significance of the differences 

 which attain to such complexity and importance in the human race, 

 we must carry our retrospect back far beyond the beginning of civili- 

 zation, and trace the growth and meaning of sex in the lower forms of 

 life. In so doing I shall ask attention to several propositions which 

 may not at first appear to have any bearing upon our subject, or any 

 very close relation to each other. I shall then try to show what this 

 relation is, and point out its bearing upon the education of women. 



Every organism which is born from an egg or seed is a resultant 

 of the two systems of- laws or conditions, which may be spoken of ab- 

 stractly as the law of heredity, and the law of variation, or, to use the 

 old teleological terms, each organism is a mean between the principle 

 of adherence to type and the principle of adaptation to conditions. 



That like produces like is universally but never absolutely true. 

 The offspring resembles its parents in all fundamental characteristics. 

 The human child, for instance, resembles its parents in the possession 

 of all the characteristics which distinguish living things from not 

 living, as well as those which distinguish animals from plants. The 

 chemical, physical, and physiological changes which take place in its 

 body and the histological structure of its tissues are like those of its 

 parents, and its various organs are the same in form and function. 

 All the characteristics which unite it with the other vertebrates, as a 

 member of the sub-kingdom Vertebrata, are like those of its parents, 

 and also those which place it in the class Mammalia, and in its proper 

 order, family, genus, and species. It also shares with its parents the 

 features or race characteristics of the particular tribe or race to which 

 they belong. If they are Chinese, Indians, or negroes, the child be- 

 longs to the same race, and manifests all the slight, superficial pecu- 

 liarities of form, constitution, and character by which that race is 

 characterized. Even the individual peculiarities of the parents, intel- 

 lectual and moral as well as physical, are now known to be hereditary. 

 Since this holds true of any other animal or plant, we must recognize 

 the universality of the law of heredity, but we must not overlook 

 the equally well-established fact that each organism is the resultant 

 of this law and another, the law of variation. The child is like its 

 parents, but not exactly like them. It is not even a compound of 

 characteristics found in one or the other of them, but has individual 

 peculiarities of its own ; slight variations which may not have ex- 

 isted in either parent, or in any more remote ancestor. The slight 



