It is, however, very doubtful if this evolution will ever go so far that the =primitive= difference between man and woman, founded as it is in the very nature of the sexual, will ever pass away. On the contrary, notwithstanding the retrogressive changes associated with the excessive development of the brain, we find that there is =an increasing differentiation of the sexes induced by civilization=. To this fact, which possesses great importance in connexion with the discussion of the woman’s question and the problem of homosexuality, W. H. Riehl, the historian of civilization, in his work on the family, published in 1885, was the first to draw attention. He devotes the second chapter of this book to the differentiation of the sexes in the course of civilized life. He was astonished by the fact that in almost all the portraits of celebrated beauties of previous centuries the heads appeared to him too =masculine= in type when compared with the ideal of feminine beauty which now appeals to us. “The medieval painters, when representing the general type of angels and saints, van Eyck and Memmling in their Madonnas and female saints, paint heads exhibiting the most clearly defined individual characteristics, but into these feeling representations of delicate virginity there intrude certain harsh lineaments, so that the heads strike us as masculine, or as a little too old. Van Eyck’s Madonnas, with the Christ-child at their breast, frequently look to us like women of thirty years old. But the painter must have followed Nature; =it is Nature which since his time has changed. The tender virgin of three hundred years ago had more masculine lineaments than she has at the present day=, and he who in the portrait of a Maria Stuart expects to find a face like one he would meet in a modern journal of fashion will find himself greatly disappointed by certain traits in the pictures of this celebrated beauty, traits which to the nineteenth century would seem almost masculine.” The contrast between the sexes becomes with advancing civilization continually sharper and more individualized, whereas in primitive conditions, and even at the present day among agricultural labourers and the proletariat, it is less sharp and to some extent even obliterated. Let the reader familiarize himself with the likenesses of modern women of the working classes; they seem to us almost to resemble disguised men. In the stature, also, of the sexes among savage peoples, and among the lower classes of the civilized nations, the sexual differences are much less marked than in our cultivated large towns. Very characteristic of the differentiating influence of civilization is, moreover, the effect on the voice. Riehl remarks on this subject: