102 INTRODUCTION. 



more so; the general texture of the parts is softer and more 

 lax; the hairs weaker and less numerous. As to the genital 

 organs, the very great differences they present, do not destroy 

 their essential analogy. The external characters of the sexes 

 we have just indicated, appear to depend upon the existence 

 and action of the ovary in woman and of the testicle in man. 

 In the embryo, where the sex is doubtful, there are no exter- 

 nal appreciable differences; in the foetus and infant they begin 

 to show themselves in proportion as the genital organs are 

 developed: in puberty the sexual characters are most perfect, 

 in old age they become less so. The want of a complete de- 

 velopment of the ovaries or testicles, their changes by disease, 

 and their ablation, likewise prevent the general differences of 

 the sexes from establishing themselves, or efface them more 

 or less completely. The causes of the difference between the 

 sexes has been sought for in a supposed predominance of the 

 coagulating principal, or of oxygen in the male and of the nu- 

 tritive matter in the female. 



112. The human species presents differences of organiza- 

 tion, hereditary in the races or varieties,* scattered over the 

 globe, and that may be considered five in number, and of 

 which there are three principal ones, viz: the Caucasian, the 

 Mongol and the Ethiopian, and the Malay and American 

 races. 



113. The Caucasian, to which we belong, is remarkable 

 for the beauty of the form and the proportions of the head, in 

 which the cranium is much larger than the face; a fact of 

 which any one will be convinced by simple inspection, as well 

 as by the application of cephalometers. The cranium is high 

 and rounded, the face is oval and its parts but slightly salient. 

 The colour of the skin is generally white and rosy; that of 

 the eyes blue or brown, that of the hair, which is generally 

 abundant, fine and long, varies from white to black. 



The Caucasian is peculiarly remarkable for the development 

 of his intelligence, for civilization and the culture of philoso- 



* See Blumenbach, op, cit- Lawrence, op. cit. 



