CLIMATE IN THE TREATMENT OF DISEASE. Broadly speaking, purity of air (i.e., freedom from solid particles and irritating gases), average temperature, range of temperature, amounts of sunshine and of humidity are the most important con siderations in the climatic treatment of disease. Social and eco nomic conditions in any given locality are important but are not discussed here. Individuals react both to heat and cold very differ ently. At health resorts, where the temperature varies between and 7o° F., strong individuals gradually lose strength, whereas a delicate person gains vigour of mind and body and puts on weight. And a corresponding intensity of cold acts in the reverse manner in each case. Thus a moderately warm health resort suits delicate, convalescent or elderly people. Cold, however, when combined with wind and damp, must be avoided by the aged, the delicate, and those prone to gouty and rheumatic affections. The moisture of the atmosphere controls the distribution of warmth on the earth, and is closely bound up with the prevailing winds, temperature, light and pressure. In dry air the evaporation from skin and lungs is increased, especially if the sunshine be plentiful and the altitude high. In warm moist air strength is lost and digestive troubles are common. In moist cold air perspiration is checked, and rheumatic and joint affections are common. The main differences between mountain air and that of the plains depend on the former being more rarefied, colder, of a lower absolute humidity, and offering less resistance to the sun's rays. As the altitude is raised, circu lation and respiration are quickened, probably as an effort on the part of the organism to compensate for the diminished supply of oxygen, and somewhat more gradually body weight and the number of red blood corpuscles increase, this increase persisting after a return to lower ground. Thus children and young people are espe cially likely to benefit by the impetus given to growth and the blood-forming organs. For older people, however, the benefit de pends on whether their organs of circulation and respiration can respond to the increased demands on them. For anaemia, pulmo nary tuberculosis, deficient expansion of the lungs, neurasthenia, and the debility following fevers and malaria, mountain air is in valuable. But where there is valvular disease of the heart, or rapidly advancing disease of the lungs, it is to be avoided. Light, especially direct sunlight, is of primary importance, the lack of it tending to depression and dyspeptic troubles. Indeed, the modern view is that the value of a climate is determined chiefly by the average intensity of ultra-violet light. Probably its germicidal power accounts in part for the aseptic character of the air of the Alps, the desert and other places.
A "good" climate is that in which all the organs and tissues of the body are kept evenly at work in alternation with rest. Thus a climate with constant moderate variations in its principal factors is the best for the maintenance of health. But the best climate for an invalid depends on the particular weakness from which he suffers. Thus in pulmonary tuberculosis a cool sunny climate is greatly superior to a tropical one. Exposure to strong winds is harmful, since it increases cough. A high altitude, from the sun shine, the purity and stimulating properties of the air, is of value to many mild or very early cases, but where the disease is extensive or the heart is irritable, or there is insomnia, high altitudes are contra-indicated. Where the disease is of long sta.iding, with much expectoration, or accompanied by albuminuria, the patient appears tc do best in a humid atmosphere but little above the sea level. The climate of Egypt is suitable for cases complicated with bron chitis or bronchiectasis, but is contra-indicated where there is at tendant diarrhoea. Madeira and the Canaries are useful when emphysema is present. Bronchitis in young people is best treated by high altitudes, but in older patients by a moist mild climate, except where much expectoration is present.
Delicate children benefit by residence at the seaside and if very delicate, with small power of reaction, the winter should be passed at some mild coast resort. Gouty and rheumatic affections require a dry soil and warm dry climate, cold and moist winds being especially injurious.
For heart affections high altitudes are to be avoided, though some physicians make an exception of mitral cases where the com pensation is good. Moderate elevations of 500 to I,5oof t. are pre ferable to the sea level.
In diseases of the kidneys, a warm dry climate, by stimulating the action of the skin, lessens the work to be done by these organs, and thus is the most beneficial. Extremes of heat and cold and elevated regions are all to be avoided. (See HELIOTHERAPY.)