Volume 1

Health lectures for the people.

Date:
1883-1892
Catalogue details

Licence: Public Domain Mark

Credit: Health lectures for the people. Source: Wellcome Collection.

    435/896 (page 183)
    ately repaired ; and in this process, which is very much a process of combustion, heat to a greater or less amount is generated. This statement is true in an especial manner of our muscular system, the part of our structure which is most universally and constantly in a state of activity. Thus the generation of heat is one of the necessary properties and accompaniments of animal life—insepar- able from it; and when life ceases the animal heat departs and cannot be revived. You cannot warm a dead body any more than you can reanimate it. But the heat thus generated does not in health accumulate within us,* but is always being given off from our bodies in various ways. Thus part of it is given off by the lungs, for the air we breathe out is warmed by it; part of it is given off by the skin, from which it radiates into the surrounding atmosphere, or is con- ducted away by cooler bodies, or is given out in the form of perspiration. Besides this, others of the natural channels of the body carry away a certain amount. It is thus evident that in the living body there is a manufacture and an expenditure of heat constantly going on. Notwithstanding this the heat of our bodies in health is a tolerably uniform quantity (98°—99° F.) whatever be the temperature of the surrounding atmosphere, and any material deviation from this betokens some departure from health. It might interest you to hear of the extremes of temperature which the human body can bear with impunity. As regards cold, the experience of Arctic voyagers is remarkable. Thus Capt. Sir John Franklin recorded a cold of —58 or 90° below freezing point; Capt. Back, —70 or 102° below freezing point; and more recently Capt. Sir George Nares, in his interesting account of his voyage to the Polar Seas, describes his experience, in March 1876, of the extraordinary temperature of 73*75 or more than 105° below freezing point. It is difficult for us, even with the experience of our most severe winters, to conceive of this amount of cold. Capt. Nares states that the very whisky froze hard, and a few of us had the rare opportunity of eating it in a solid state. The * It has been estimated that if this heat were allowed to accumulate within us, and none to be given off, it would be sufficient to raise the body to the boiling point in thirty-six hours.