Physiological Actions

It is difficult to assign heat to its proper position in a systematic classification. As a stimulant to the vital processes, it pertains to the class of agents promoting constructive metamorphosis; but, in its influence on the interchanges of repair and waste, the action quickly passes into the stage of waste. As its therapeutical employment is almost entirely confined to the range of constructive metamorphosis, it seems more appropriate to embrace it in this division of the subject.

The normal heat-production of the body varies singularly little in health. Every considerable rise of temperature above, every considerable fall below, the normal of 98·5° Fahr., indicates the existence of disease. The various external causes of disturbance of the heat-producing function of the body do not, in health, affect the normal standard, because of the existence of a regulating apparatus. Every one is familiar with the fact that the human body can be exposed, without risk, to a temperature much above its own standard, provided the heat-regulating function is in a condition of healthy activity. If, however, the transmutation of heat into another mode of motion can not be effected, then the complexus of morbid actions, called fever, is at once established. Every increment of heat added to the body, unable to transmute it into another mode of motion, adds to the existing temperature.

Very important alterations take place in a body, the seat of a febrile process. Increased waste, the result of more rapid oxidation, occurs; the excretion of urea, and, according to some authorities, of carbonic acid, is increased; and those important and wide-spread lesions, entitled parenchymatous degenerations, develop in various organs of the body.