_Lack of Light_.--People who work at occupations that keep them from the light are likely to suffer from lung symptoms and to have quite intractable colds which will not clear up until they get more sunlight. Workers in theaters and like places who do their sweeping where sunlight does not penetrate, are in more danger than others from respiratory disease. Those who work in gloomy lower stories, especially in narrow but busy and dusty streets, suffer the same way. Attendants at moving picture shows who work much in the dark where the frequently changing crowd brings in dust which cannot be well removed, and in quarters where the sun does not penetrate, are almost sure to have persistent repeated respiratory troubles. _Habitual Movements_.--After the question of dust comes the mode of the occupation. Many occupations demand certain habitual and repeated movements. When people come complaining of pains in muscles in and around joints, or of achy conditions in the limbs, it is important to know every detail of their occupation movements, if the physician is to appreciate just what pathological causes are at work. It is not enough, for instance, to know that a man is a clerk, or a bookkeeper, but it should be asked whether he stands much at his occupation, or walks considerably, or whether he sits practically all the day. If he stands much, we can expect that he will have various painful conditions in his feet and legs, unless he takes care to change his position frequently, to wear the most comfortable shoes obtainable and, above all, to provide against any yielding of the arch of the foot. Often it will be found that people who complain of discomfort in the feet stand much on a cold, and sometimes damp and draughty floor, and this needs to be corrected or their symptoms, often carelessly called rheumatic, will not disappear. If he sits down always during his occupation, he will need exercise and air or he will suffer from many vague discomforts, over sensitiveness and irritability of nerves, as well as from physical conditions.