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This reversion—growing hair again on the scalp—was, at 
first, an adult feature; and it became earlier as the phylo- 
genetic series progressed. Not improbably it was aided by 
sexual selection. Later still, hair made its appearance on other 
parts of the body and limbs—notably, however, where hair had 
probably been very feebly developed in the earlier members of 
the phylogenetic series. As an instance of this take the hair 
beneath the arms—a place very bare in quadrupeds.* 
Still later in the phylogenetic series the moustache and 
beard reappeared in the male. Finally, there is an appearance 
of hair on the chest; and a loss of hair from the head. 
The latter is principally confined to the male, which fact 
makes it possible that the female first acquired this ornament. 
The hair departs from the head where it appears latest in the 
infant, and, therefore, presumably latest in the phylogenetic 
series—namely, the temples. Then the scalp becomes affected. 
In considering the various appearances and disappearances 
of hair from Man it is worth noticing how little the popular 
explanations of baldness—wearing hats, machine-brushes, and 
other absurd reasons—can have affected the matter. Not only 
do the classes—who are bald—wear hats much less than the 
masses, who are but little affected in this way; but in spite of 
wearing a continuous covering like clothes, Man becomes 
decidedly more hairy on the body as he grows older. 
Tae Direction In wuicH Harr Grows. 
- I have a few words to say concerning the arrangement of 
hair in Man. In the first place, however, it is necessary 
to consider the laws which would govern the direction assumed. 
These would be :— 
1.—Gravity. 
2.—Influence of surrounding media. 
3.—Muscular action, and the amount of secretion. 
4,— Heredity. 
[* It is curious that the parts almost bare when the others where hairy 
should become hairy when the others are bare. The inside of thighs is another 
example, It looks like compensatory development. | 
