Body temperature

“ The factors governing the temperature of the body are the amount of heat produced and the amount lost. If more heat escapes, more has to be generated; and the source of all the heat produced in the body is the food taken. This becomes changed by the metabolic processes occurring in the body which produce heat.
Heat is lost, (1) by the skin; (2) in respiration, the expired air having been heated during its stay in the lungs; (3) with the food and drink taken, if not at the temperature of the body; (4) with the excreta; and (5) by transformation of heat into mechanical energy. ”

“ The functional activity of no other gland of the body alone, and the secretion of no other gland alone, can cause a comparable rise in body temperature—that is, neither increased functional activity nor any active principle derived from the kidney, the liver, the stomach, the pancreas, the hypophysis, the parathyroids, the spleen, the intestines, the thymus, the lymphatic glands, or the bones can, per se, cause a rise in the general body temperature comparable to the rise that may be caused by the activity of the brain or the muscles, or by the injection of adrenalin or thyroid extract. ”

“ As the warm blood recedes from the skin, a sensation of cold is felt, but when the blood returns, there is again the feeling of warmth. The sensation of cold prompts one to seek a warmer place, or to put on more clothing; while the sensation of heat, if it be oppressive, leads to activities of an opposite kind. Prompted in this way by the sensations from the skin, one voluntarily supplies the external conditions, such as clothing and heat, that affect the body temperature. ”

“ The warm-blooded animals, birds and mammals, have the remarkable power of keeping the body temperature constant (at 98-99 degrees Fahrenheit, in man, somewhat higher in birds) , in spite of great variations in the external temperature to which the body is exposed, and in spite of great variations in the {142} amount of heat generated in the body by muscular exercise. ”

“ Reduction of Temperature.—The body's temperature is normal when in the armpit it is about 95° Fahr. Food and drink are stimulants, and the skin is the radiating surface which gives off the surplus heat. If this elimination is not sufficiently active, the body becomes overheated, and this manifests itself by shivering. Overheating is the result when one eats and drinks much, at the same time parting with but little heat. ”

“ On the other hand, it has been ascertained by numerous and well-conducted experiments, that the human body can 254 be exposed, even for a length of time, to a very high temperature, without essentially elevating that of the body. ”

“ The faculty of generating heat explains how it is that we are enabled to resist the effects of cold; but how does the body withstand a temperature higher than its {145}own? Men have been known to remain several minutes in an atmosphere heated above the boiling-point of water, and yet the temperature of their own bodies was not greatly elevated. Those who labor in foundries and glass-works are habitually subjected to very high degrees of temperature, but they do not suffer in health more than those engaged in many other occupations. ”

“ When cold air comes in contact with the skin and mucous membrane of the lungs, heat is removed from the body, as from a stove, to restore an equilibrium of temperature. The removal of heat from the body is greatest when we are in a current of cold air, or when a brisk, cold wind is blowing upon us. ”

“ A person [64] who, after exercise that has produced free perspiration, stands in a current of cool air, is apt to take cold. The dryer the atmosphere, the more rapid is the cooling process. The most uncomfortable and oppressive atmospheric condition is that in which the air is heavily laden with moisture and the temperature high. Evaporation from the body is then slow, and the sensation of heat is oppressive.
It is a mistaken notion that clothing keeps the cold out. Its purpose is to keep the heat in, or, in other words, to prevent the rapid radiation of heat. ”

“ This heat can not be supplied artificially from without. It must be generated within the body. It therefore becomes obvious that the temperature outside of the body is not regulated for the purpose of supplying the body with heat. ”

“ Upon touching my side, it felt cold like a corpse; and yet the actual heat of my body, tried under my tongue, and by applying closely the thermometer to my skin, was 98 deg., about a degree higher than its ordinary temperature. When the heat of the air began to approach the highest degree which the apparatus was capable of producing, our bodies in the room prevented it from rising any higher ”

“ Did not the human body possess within itself the power of generating and removing heat, so as to maintain nearly an equality of temperature, the most fatal consequences would ensue. In northern latitudes, especially, in severe weather of winter, the blood would be converted into a solid 255 mass, and on the other hand, the fatty secretion, when subjected to equatorial heat, would become fluid, and life would be extinguished. ”

“ In what manner should change of temperature take place, to be adapted to the body? How is the body enabled to endure tropical heat and polar cold? State some of the effects of the gradual adaptation of the system to different temperatures. ”

“ I am well persuaded that the skin would resist also less, at this age, a degree of temperature greater than that of the body, and as it permits the internal caloric to be easily lost in a colder medium, it would allow the external to penetrate in a warmer one. ”