HOW SOME FAMILIAR THINGS LOOK 109 
hair under the microscope can recognize the 
hair of any animal by the markings on it with¬ 
out being told what animal the hair came from. 
From above, a piece of our skin shows a rather How does 
irregular surface, under the microscope. There s ^ in a PP ear? 
are numerous small openings to little sweat 
glands in it and many tiny hairs stick out. The 
skin looks greasy and wrinkled and not at all 
like the smooth skin we see with our naked 
eyes. If we could slice off a piece crossways, as 
scientists have done, and examine it, we would 
find that the skin has a hard, horny, almost 
transparent outside layer. Under this protec¬ 
tive layer is a softer layer of tiny cells and below 
that, cells of the fat and tissue that form the 
body. The soft middle layer has many deep 
sockets in it in which are embedded the roots 
of the hairs. Through it run little tubes which 
are the sweat glands. 
In the cells just under the outside layer are 
little grains of the same kind of coloring mate¬ 
rial as is in our hair—pigment. When there 
is only a little pigment, the blood shines through 
