This coincides with the fact to which we have already alluded, that woman as compared with man possesses less variability, that she is the simpler, more primitive being. Similarly, experience teaches ethnologists that the men of a race differ from one another to a much greater extent than the women.[22] If we wish to sum up in a word the =nature= of the physical sexual differences, we must say: =Woman remains more akin to the child than man.= This, however, in no way constitutes an inferiority, as Havelock Ellis and Oskar Schultze have convincingly shown. It is only the expression of =a primitive difference in nature=, brought about by the adaptation of the female body to the purposes of reproduction. This is the cause of the more infantile habitus of women (according to the above-quoted biological law of Herbert Spencer). The observation of the physical differences between man and woman also teaches us the futility of the old dispute as to whether man’s body or woman’s was the more beautiful.[23] The different tasks which lie before the male and female bodies respectively give rise to different development of individual parts. If this development is complete in its kind, the body is beautiful. Stratz, in the introduction to his book on “The Beauty of the Female Body,” has rightly =identified perfect beauty with perfect health=. Man’s body and woman’s will alike be beautiful if all secondary sexual characters are developed in a harmonious and not excessive degree, if the idea of “manliness in man” and “womanliness in woman” have attained full expression, and have not been unduly limited by isolated peculiarities and variations. Masculine and feminine beauty are different. There can be no question regarding the superiority of one or the other.