4 THE STRUCTURE OF MAN 
mentioned, hair is frequently strongly developed on the ventral 
and dorsal regions of the trunk, 2.e. on the breast and abdomen, 
and on the buttocks and neck, and on the limbs. 
These facts alone would suffice to render it probable that 
man was in primitive times far more hairy than at present, but 
still stronger evidence can be brought forward. 
Fig. 1.—FAcE OF AN EMBRYO FIVE MONTHS OLD, with the embryonic covering 
of hair. (After Ecker.) 
The first traces of hair appear, in the human embryo, as early 
as the twelfth or thirteenth week, the earliest being found about 
the forehead, the mouth, and the eyebrows, 7.e. in those parts of 
the body where, in the lower Mammals, the so-called “ whiskers ” 
(vibrissee) or tactile hairs usually appear. It is evident that, 
morphologically, the hairs about the mouth and eyebrows in Men 
belong to this same category. The hairs begin to break through 
the integument at the end of the fifth month, and they con- 
tinue to do so till the seventh month, those of the head being the 
earliest and those of the limbs the latest to appear In the 
1 The fact of the appearance of hair in different parts of the body in regular 
order, the lower limbs being the last to become thus clothed, has apparently attained 
popular recognition in the very old proverb ‘‘he has hair on his toes,” which may 
doubtless be referred to a time when boots and shoes did not play the part they now 
do. From what I have gathered in conversation with inhabitants of Berne (Ober- 
