GENERAL OBSERVATIONS 4T 
for its nourishment upon the indirect supply it receives 
from the vessels of the corium. The need for extreme 
vascularity of the corium is further explained when we call 
to mind the constant proliferation and casting off of the 
cells of the epidermis, the growth of the hairs, the pro- 
duction of the horn of the hoof, and the work performed by 
the numerous sweat and other glands. 
Others of the papille contain nerves, ending here in 
tactile corpuscles, or continuing, as we have mentioned 
before, to ramify as fine fibrils in the rete mucosum of the 
epidermis. 
Tue Harrs are growths of the epidermis extending 
downwards into the deeper part of the corium. Each is 
developed in a small pit, the Hair Follicle, from the bottom 
of which it grows, the part lying within the follicle being 
known as the Root. It is important to note their structure, 
as it will be seen later thut they bear an extremely close 
relation to the horn of the hoof. 
Under a high power of the microscope, and in optical 
section, the central portion of a hair is tube-like. In some 
cases the cavity of the tube is occupied by a dark looking 
substance formed of angular cells, and known as the 
Medulla. The walls of the tube, or the main substance of 
the hair, is made up of a pigmented, horny, fibrous material. 
This fibrous structure is covered by a delicate layer of 
finely imbricated scales, and is termed the Hair Cuticle. 
The root of the hair, that portion within the follicle, has 
exactly the same formation save at its extreme end. Here 
it becomes enlarged into a knob-like formation composed 
of soft, growing cells, which knob-like formation fits over 
a vascular papilla projecting up in the bottom of the 
follicle. 
We have already stated that the hairs are down-growths 
of the epidermis. It follows, therefore, that the hair 
follicles, really depressions or cul-de-sacs of the skin itself, 
are lined by epithelial cells and connective tissue. So 
closely does the epidermal portion of the follicle invest the 
hair root that it is often dragged out with it, and is known 
