Page:Popular Science Monthly Volume 2.djvu/426

410 of from half a degree to a degree, during three or seven days, at the end of which time the disorder has run its course. When the temperature gradually rises after the third day, a fatal result may he expected. Persistent heat in that case is the precursor of death. Eruptive fevers, like small-pox, scarlatina, and measles, present very important phenomena of heat. In these heat begins with the attack of the malady, and increases till the cutaneous eruption occurs. It keeps up at a maximum, which reaches 42½° (in scarlatina), till the eruption is complete, then it begins a declining course, variable with the phases of the eruption, which finishes either with scaling off as in scarlatina, or suppuration as in small-pox. And the temperature rises also in several surgical affections, bringing on a more or less inflamed and feverish condition. This is observed in wounds, and generally in every kind of traumatism, in tetanus, aneurisms, etc. In the case of strangulated hernia and of burns, and in most cases of poisoning, on the other hand, it declines in a remarkable way.

Very plainly this rising and falling of animal warmth in diseases can only be attributed to a corresponding state occurring in the energy of respiratory combustion. We do not yet exactly know the cause of these variations; that is, the mechanism by which the morbid influences stimulate or check the active production of heat. Some physicians see in it the effect of fermentations occasioned in the blood by certain microscopic beings, such as bacteria and vibriones, which may perhaps be supposed to be the fact in most febrile maladies. Others assume that, in local inflammations, it is the inflamed organ which communicates heat to the whole body, as a furnace does in a confined space. To others the disturbance seems rather to have a nervous origin, since the nerves, as we have seen, are the regulators of thermic action.

The use of the thermometer is the only exact method of measuring the temperature in diseases. Swammerdam, in the middle of the seventeenth century, seems to have been the first to have the idea of it. De Haën and Hunter, in the last century, used it in their medical practice, but its employment at the sick-bed has really only come into importance in our own day, thanks to the labors of Bouilland, Gavarret, Roger, Hirtz, and Charcot, in France; Bärensprung, Traube, and especially Wunderlich, in Germany. These physicians were not content with proving that the temperature in illness rises several degrees; they followed the variations of the thermometer day by day, hour by hour, in the different phases of the pathologic movements. They discovered that the curves of these oscillations furnish constant types for each disease, which are modified in a regular manner, according as the disease has been left to itself or treated by one or another medicine. By the study of these pathologic curves of heat the course of diseases may be followed, and valuable indications noted in diagnosis or prognosis. In hæmorrhage of the brain, for instance, the temperature falls