406 
DIGESTIVE ORGANS AND FOOD 
test. This experiment will prove that we do not taste flavors. Remove 
the hand from the nose and again taste the same substances. This 
time there will be no difficulty in telling the name of the substance 
because it has been smelled as well as tasted. 
The roof of the mouth is called the palate. The front 
part contains supporting plates of bone and is therefore 
called the hard palate. The back part (the soft palate) is a 
thin sheet of muscle covered by the 
mucous (mu'kus) lining of the mouth. 
The soft palate separates the mouth 
from the nasal cavity. Beyond the 
soft palate is the throat cavity called 
the pharynx. This is a funnel-shaped 
cavity, having two openings at its 
lower end, the front one being the 
opening into the windpipe which leads 
to the lungs, and the rear one, the 
opening into the esophagus. In the 
Figure 366. — X-ray of , £ ,, , . 
Three Teeth. upper part oi the pharynx, on each 
side, is the opening of a Eustachian 
(u-sta'ki-an) tube which passes to 
the middle ear. 
Teeth. — Just back of the lips are 
the teeth. In adults there are thirty- 
two, sixteen in each jaw, belonging 
to four classes according to shape. 
In front are the eight incisors (in- 
sl'zers) with sharp cutting edges; next the four sharp-pointed 
canines (ka/nins), and back of the canines the eight pre¬ 
molars (pre-mo'lers) shaped for tearing and crushing, while 
the remainder of the teeth, twelve in number, are the flat- 
topped molars which do most of the grinding of the food. 
Care of the Teeth. — We all know that the teeth are hard. 
Note how firmly the 
bone fits around the roots. 
These teeth are in good 
condition. The white 
blotches on the molar tooth 
are the places where this 
tooth has been filled. This 
is the new way of examin¬ 
ing the teeth. 
That, however, does not prevent them from becoming broken 
by carelessness or accident, or from decaying because of 
