The above rules embody our preachment on individual hygiene. We have stated them as fifteen separate kinds of procedure. In actual life, however, our acts can not be so separated. The neglect or observance of one rule carries with it, to some extent, the neglect or observance of other rules. For instance, one can not take muscular exercise without, to some extent, taking breathing exercises. Swimming serves as a means of cleanliness, of skin gymnastics, of general exercise and of amusement. A game of tennis implies the practise, to some extent, of at least five of the fifteen rules. The human body is a "harp of a thousand strings," which are intended to harmonize. If one of them is out of tune, it is likely to cause discord throughout, while to tune up one helps the harmony of all. [Sidenote: Medical Specialists] Any one ailment has a far-reaching effect throughout the system. It is because of this far-reaching effect that the "one idea" specialist in medicine has so often thought his particular specialty to be the one and only gateway to all therapeutics and hygiene. The oculist is liable to look at all ailments as related to the eyes; the dentist as related to the teeth; the mental hygienist as related to wrong attitudes of mind. If we examine their claims, we find that they are usually right in their affirmations, though wrong in their denials. It is their affirmations in which we are here interested. They find that the ailments within their own special province extend in unsuspected ways, and to a surprising degree into seemingly remote fields; and that to remedy the special defect which they can treat, will often go a long way toward remedying numerous other ailments. [Sidenote: Remote Effects of Ailments] It has already been noted that eye-strain leads to an astonishing number of serious nervous affections, and that corrective eyeglasses will often work wonders for remedying those ailments and improving the general health. There may be other unhygienic conditions equally responsible for these symptoms, and the correction of which may produce equally wonderful improvement. Vertigo may be due to eye-strain, or it may be due to wrong posture or to pressure of wax on the ear-drum. Diabetes may be aggravated by too much sugar, by infected tooth-sockets, or by too much worry. Tuberculosis may be due jointly to indoor-living, lack of exercise, wrong diet, wrong posture, sexual excess, alcohol, nerve-strain, and numerous other preconditions, besides infection with the tubercle bacillus. The social evil can be fought not only directly by attack on prostitution, and by appeals to self-control and moral ideals, but also indirectly by diminishing the consumption of alcohol and other drugs, for alcohol not only produces abnormal sexual desire but reduces the strength of will by which that desire is repressed. Forel asserts that the social evil can not be controlled until the use of alcohol as a beverage is abolished.