How far away can you read these letters? Measure the distance. Twenty feet is a test for the normal eye.
Defects in the Eye.—In some eyes, the lens is in focus for near objects, but is not easily focused upon distant objects; such an eye is said to be nearsighted. Other eyes which do not focus clearly on objects near at hand are said to be farsighted. Still another eye defect is astigmatism, which causes images of lines in a certain direction to be indistinct, while images of lines transverse to the former are distinct. Many nervous troubles, especially headaches, may be due to eye strain. We should have our eyes examined from time to time, especially if we are subject to headaches.
The Alcohol Question.—It is agreed by investigators that in large or continued amounts alcohol has a narcotic effect; that it first dulls or paralyzes the nerve centers which control our judgment, and later acts upon the so-called motor centers, those which control our muscular activities.
The reason, then, that a man in the first stages of intoxication talks rapidly and sometimes wittily, is because the centers of judgment are paralyzed. This frees the speech centers from control exercised by our judgment, with the resultant rapid and free flow of speech.
In small amounts alcohol is believed by some physiologists to have always this same narcotic effect, while other physiologists think that alcohol does stimulate the brain centers, especially the higher centers, to increased activity. Some scientific and professional men use alcohol in small amounts for this stimulation and report no seeming harm from the indulgence. Others, and by far the larger number, agree that this stimulation from alcohol is only apparent and that even in the smallest amounts alcohol has a narcotic effect.
The Paralyzing Effects of Alcohol on the Nervous System.—Alcohol has the effect of temporarily paralyzing the nerve centers. The first effect is that of exhilaration. A man may do more work for a time under the stimulation of alcohol. This stimulation, however, is of short duration and is invariably followed by a period of depression and inertia. In this latter state, a man will do less work than before. In larger quantities, alcohol has the effect of completely paralyzing the nerve centers. This is seen in the case of a man "dead drunk." He falls in a stupor because all of the centers governing speech, sight, locomotion, etc., have been temporarily paralyzed. If a man takes a very large amount of alcohol, even the nerve centers governing respiration and circulation may become poisoned, and the victim will die.
Effect on the Organs of Special Sense.—Professor Forel, one of the foremost European experts on the question of the effect of alcohol on the nervous system, says: "Through all parts of nervous activity from the innervation of the muscles and the simplest sensation to the highest activity of the soul the paralyzing effect of alcohol can be demonstrated." Several experimenters of undoubted ability have noted the paralyzing effect of alcohol even in small doses. By the use of delicate instruments of precision, Ridge tested the effect of alcohol on the senses of smell, vision, and muscular sense of weight. He found that two drams of absolute alcohol produced a positive decrease in the sensitiveness of the nerves of feeling, that so small a quantity as one half dram of absolute alcohol diminished the power of vision and the muscular sense of weight. Kraepelin and Kurz by experiment determined that the acuteness of the special senses of sight, hearing, touch, taste, and smell was diminished by an ounce of alcohol, the power of vision being lost to one third of its extent and a similar effect being produced on the other special senses. Other investigators have reached like conclusions. There is no doubt but that alcohol, even in small quantities, renders the organs of sense less sensitive and therefore less accurate.
Table to show a comparison of chances of illness and death in drinkers and non-drinkers. Solid black, drinkers. (From German sources.)
Effect of Alcohol on the Ability to Resist Disease.—Among certain classes of people the belief exists that alcohol in the form of brandy or some other drink or in patent medicines, malt tonics, and the like is of great importance in building up the body so as to resist disease or to cure it after disease has attacked it. Nothing is further from the truth. In experiments on a large number of animals, including dogs, rabbits, guinea pigs, fowls, and pigeons, Laitenen, of the University of Helsingsfors, found that alcohol, without exception, made these animals more susceptible to disease than were the controls.