~28. Bad Tastes.~--People sometimes learn to like things which have a
very unpleasant taste. Pepper, mustard, pepper-sauce, and other hot
sauces, alcohol, and tobacco are harmful substances of this sort. When
used freely they injure the sense of taste so that it cannot detect and
enjoy fine and delicate flavors. These substances, as we have elsewhere
learned, also do the stomach harm and injure the nerves and other parts
of the body.

~29. The Sense of Touch.~--If you put your hand upon an object you can
tell whether it is hard or soft, smooth or rough, and can learn whether
it is round or square, or of some other shape. You are able to do this
by means of the nerves of touch, which are found in the skin in all
parts of the body. If you wished to know how an object feels, would you
touch it with the elbow, or the knee, or the cheek? You will say, No.
You would feel of it with the hand, and would touch it with the ends of
the fingers. You can feel objects better with the ends of the fingers
because there are more nerves of touch in the part of the skin covering
the ends of the fingers than in most other parts of the body.

~30.~ The sense of touch is more delicate in the tip of the tongue than
in any other part. This is because it is necessary to use the sense of
touch in the tongue to assist the sense of taste in finding out whether
things are good to eat or not. The sense of touch is also very useful to
us in many other ways. We hardly know how useful it really is until we
are deprived of some of our other senses, as sight or hearing. In a
blind man the sense of touch often becomes surprisingly acute.

~31. Effects of Alcohol and Tobacco on the Special Senses.~--All the
special senses--hearing, seeing, smelling, tasting, feeling--depend upon