This section is from the book "The Home Hand-Book of Domestic Hygiene and Rational Medicine. Volume 2.", by J. H. Kellogg, M.D.. Also available from Amazon: The Home Hand-Book of Domestic Hygiene and Rational Medicine, Volume 2.
The above are the symptoms characteristic of fever, a condition which is present in nearly all the diseases included in this section. In the various febrile diseases, numerous other symptoms arise in addition to those which pertain to fever itself, varying according to the particu lar affection or the local complications which may arise. Fever is generally understood to be a general disease of the blood. In the majority of cases, its cause is the introduction into the system of poisonous or morbid elements of some sort. When the poison thus received into the system is of an animal or vegetable nature, reproduction usually takes place, occasioning a great increase in the quantity of the morbid element. This explains the fact that a certain period, varying from a few hours or days to several months, almost always elapses after the morbid elements are received into the system before the chief symptoms of the disease make their appearance. This is called the period of incubation.
The natural temperature of the body, when taken under the tongue or in the arm-pit, is 98 1/2°. Only very slight variations occur in health. When the temperature rises to 100° or more, the pulse will almost invariably be found to be increased in frequency. The frequency of respiration will also be increased, and other symptoms of fever will generally be found. It may happen, however, that the increased temperature, as detected by the thermometer, will be the only febrile symptom which can be readily detected at the very beginning of febrile disease, since this is by far the most delicate and reliable means for determining the degree or intensity of febrile action. Fig. 336 shows one of the latest forms of fever thermometer which has been devised. Every family should possess a reliable instrument of this kind, as, by its aid, the first beginnings of disease may sometimes be detected. In using the thermometer, care is necessary to secure correct results. If the instrument be placed in the arm-pit, the arm should be drawn close to the body, with the fore-arm drawn across the chest, so as to cover the instrument as completely as possible. It should be retained in position eight or ten minutes. It is often more convenient to take the temperature in the mouth, the bulb of the thermometer being placed under the tongue, the lips of the patient being kept tightly closed for five or ten minutes. In young infants, the thermometer may be introduced into the rectum. In this location, the temperature is found to te about a degree higher than in the mouth or arm-pit. Before placing the thermometer in position, if it is a self-registering instrument, and no other should be employed, care should be taken to shake the index down to 90° or 95°, reading from the upper end of the index, which consists of a short column of mercury detached from the main column.
Fig. 336. Fever Thermometer.
A very accurate idea of the temperature of the body may generally be obtained by means of the hand, if proper precautions are taken to avoid error. In order to judge correctly of the temperature, the hand should be perfectly clean, smooth, and dry, and should be properly warmed before applying to the body; as, if the hand happens to be cold, the body may feel unnaturally hot, although of normal temperture. First, one or two fingers, and then the whole flat surface of the hand should be laid upon the body.
The variations of temperature from that of health differ in various febrile diseases, in some running very high, while in others only a very moderate degree of elevation is noticed. As a general rule, the temperature does not rise above 103° to 105°. A temperature over 107° is very likely to prove fatal, although cases have been known to recover in which the temperature has risen two or three degrees higher. In depression, the condition opposite that of fever, the temperature is lower than normal, sinking even as low as 94° or 95°, or even lower. A very low temperature is as grave a symptom as a very high one; but occurs much less frequently.
The general supposition that a chill is the opposite of fever, is an error. The thermometer shows that the temperature is elevated during a chill as well as during a fever. The temperature may not rise as high, but is considerably above the normal standard. In most of these cases, the thermometer is of course the only reliable means 6f determining the temperature, as the skin is, not infrequently, cold and the patient shivering, while the internal temperature of the body is much higher than in health.