~27.~ The use of the sense of taste is to give us pleasure and to tell us whether different substances are healthful or injurious. Things which are poisonous and likely to make us sick almost always have an unpleasant taste as well as an unpleasant odor. Things which have a pleasant taste are usually harmless. ~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 the brain and nerves. Whatever does harm to the brain and nerves must injure the special senses also. We have learned how alcohol and tobacco, and all other narcotics and stimulants, injure and sometimes destroy the brain cells and their nerve branches, and so we can understand that a person who uses these poisonous substances will, by so doing, injure the delicate organs with which he hears, sees, smells, etc. ~32.~ Persons who use tobacco and strong drink sometimes become blind, because these poisons injure the nerves of sight. The ears are frequently injured by the use of tobacco. Smoking cigarettes and snuff-taking destroy the sense of smell. The poison of the tobacco paralyzes the nerves of taste so that they cannot detect flavors. Tea-tasters and other persons who need to have a delicate sense of taste do not use either alcohol or tobacco. SUMMARY.