Action, Balance of.--An excellent guide to the proper treatment of any case is to be found in the distribution of heat in the patient's body. Hot parts are to be cooled, and cold parts warmed, often both at the same time, so as to restore the proper balance of vital action. _Gentle progressive_ measures are always best in this, especially with children. Cold feet are warmed by BATHING (_see_) and FOMENTATION (_see_). A heated head may be cooled with COLD TOWELS (_see_) or with soap LATHER (_see_). This principle of seeking a proper balance should be borne in mind throughout all our treatment. Its importance can hardly be exaggerated, as the restoration of this balance alone will frequently effect an almost magical cure where drugs have been wholly ineffective.
Air.--The Black Hole of Calcutta is an object lesson of how necessary to life is the renewal of the air supply. Few people, however, reflect that a deficient supply of fresh air may affect the health, though far short of what will cause death. Many hospitable people will invite so many friends to their houses that the amount of air each can get is less than 1-20th of what the law insists shall be provided for the prisoners in our gaols. Superabundant provision is made for the wants of the stomachs of these guests, but none at all for the more important organ--the lungs. The headaches and lack of appetite next morning are attributed to the supper instead of the repeatedly breathed air, for each guest gives off almost 20 cubic feet of used-up air per hour. No one would ask their guests to wash with water others had used; how many offer them air which has been made foul by previous use? Everyone knows that in our lungs oxygen is removed from the air inhaled, and its place taken by carbonic acid gas. Besides this deoxydizing, the air becomes loaded with organic matter which is easily detected by the olfactory organs of those who have just come in, and so are in a position to promptly compare the air inside with what they have been breathing. The exhilaration produced by deep breathing of pure air is well known. What, therefore, prevents everyone enjoying it at all times? Simply the fear of "cold"--an unfortunate name for that low form of fever properly called catarrh, and a name which is largely responsible for this mistaken idea. "Colds" are now known to be infectious, being often caught in close ill-ventilated places of public assembly. Most people suppose that it is the change from the heat to the cold outside that gives them "cold," whereas the "cold" has been contracted inside. There is no lack of evidence that wide open windows day and night, summer and winter, so strengthen and invigorate that colds are rarely taken, and when taken, generally in a mild form. This also applies to influenza. If delicate consumptives can stand, without any gradual breaking-in to it, unlimited fresh air, and can lie by day and night in open sheds, no one need dread at once to adopt the open-window system. Although few will believe it, until they try it, a wide open window does not produce a draught as does one slightly opened, and it is safer and pleasanter to go in for abundant fresh air than to try what might be called a moderate course. Many think that with an open window the heat of the fire is practically wasted. They do not know that the _radiant_ heat of the fire will warm the person it falls on even though the temperature of the room is very low. The Canadian hunter before his fire is comfortably warm, though the air around him may be a long way below zero. Extra clothing may be worn if any chilliness is felt. While the body is warm cold air has an invigorating effect on the lungs. Indeed, the body soon gets accustomed to the colder air, and those who practise keeping open windows winter and summer find that they do not require heavier clothing than those who sit with windows shut. A slight or even considerable feeling of coldness, when due to cold air and not to ill-health, will not harm.