202 HOUSE, GARDEN, AND FIELD 



trees are willows and birches, which do not rise nearly 

 so high above the ground as the grass in an English 

 meadow. 



Sycamore, lime, the great willows and poplars, elm and 

 witch elm are all more or less doubtful natives. Spanish 

 chestnut, horse-chestnut and walnut, besides many others, 

 are known to have been introduced by man. All our 

 horse-chestnuts, for example, are said to be descended 

 from a tree which was brought to Constantinople in 1557, 

 probably from some part of Turkey. (See p. 61.) 



XXXVI. THE HUMAN FACE. 



Take a concave mirror, such as is now sold as a shaving- 

 glass, and in this carefully survey your own face. The 

 concave mirror enlarges any part of the face that you 

 wish to study closely. 



You will see that everywhere, even on the forehead and 

 the ridge of the nose, which to ordinary inspection are 

 quite bare, there are either hairs, or the little pits which 

 mark the places of old hair-follicles. In most people, 

 whether old or young, male or female, the cheeks are 

 downy. I can often see exactly how far a man's razor 

 reaches, for though the edge of the shaven tracts comes 

 in a part of the face where hairs cannot be discerned by 

 the naked eye, the downy part of the cheek reflects the 

 light differently from the clean-shaven part. In human 

 embryos the face is covered with plainly visible down, 

 only the red edges of the lips being completely bare. At 

 this time the whole body is hairy, except the palms of 

 the hands and the soles of the feet. 



It would be hard to explain the distribution of strong 

 hairs upon the human head. The bare face was probably 

 developed by sexual selection, those suitors being pre- 

 ferred who showed it most plainly, and this explanation 

 may apply to all the other details. The recesses beneath 



