26 TRICHOLOGIA MAMMALIUM ; 
CHAP Tk lt: 
PiLeE is an animal apparatus, consisting of several organs, distinguishable by different 
membranes, but acting unitedly to accomplish destined ends. It possesses, per se, no 
sensation nor power of voluntary motion; but is connected with a tissue rich in vessels 
and nerves. 
That Pile is not vegetable, as was anciently supposed, is proved by 
The manner in which the Shaft elongates —Hair does not grow by additions to its points, 
like the roots of vegetables; nor by a s¢multaneous elongation of the whole shaft, like their 
stems ; but by additions at the LOWER EXTREMITY, So that the newly produced portions are 
continually forcing the old ones forward. ‘This is the reason why no injuries, such as 
splitting at the apex; nor any losses, such as a deprivation of the point of pile, can ever 
be repaired. If the natural point of a hair (which is the first part of the stalk that is 
produced) be, accidentally or intentionally, removed, it is never repaired. ‘This is also the 
reason why hair, which has been dyed, shows its undyed color first nearest to the skin ; 
and why marks, made upon the fleece of sheep, become, in time, obliterated, beginning to 
blanche near the body of the animal. 
This property of growing by additions at the lower extremity, only, distinguishes pile 
from vegetables, and is capable of being made use of as one of the tests of a true hair. 
OF THE DIFFERENT PARTS OF PiLe.—Pile, when in a normal and healthy condition, 
and fully developed, has the following parts :-— 
A shaft,—at the inferior extremity of which is a button, and at the superior one a pornt. 
This shaft has a cortex, which is either squamose or paved,—intermediate fibres, which 
are divisible into fibrils, and a centre, which is either solid or has a canal. ‘The canal 
(when present) either contains a granulated substance and pigment cells, or a granulated 
substance and no pigment cells—or, the canal is void. 
The button, with the lower extremity of the shaft, is set ina follicle, which has a double 
lining membrane, called a sheath. 
Recapitulation :— 
1. SHAFT. 
1. Button. 
2. Point. 
3. Cortex. 
1. Squamose. 
2. Paved. 
4. Intermediate fibres and fibrils. 
