Chapter XIV: Appendix: D

THE CLINICAL THERMOMETER.

The possession of a self-registering Clinical Thermometer in every household, in a tropical or malarious climate is a necessity, more especially when at a distance from medical aid. It is a means for assisting to ascertain most accurately, in a very few minutes, whether a child or patient is really ill, and the necessity there might be for the administration of remedies; for calling in other and more proficient assistance; or to allay anxiety that might have accrued from a nervous fear, when possibly no actual illness existed.

From one single observation of an _abnormal_ temperature, we learn:

"1. That the patient is really bodily ill.

"2. When there is considerable elevation of temperature, we know that there is fever.

"3. When there are extremes of temperature, we know that there is great danger.

"The mean normal temperature of the human body in health is 98·6° Fahrenheit's scale."[5] This may vary in health, in exceptional cases from 97·5° to 99·5° Fahrenheit.

The accompanying diagrams represent (_A_) a thermometer that has been employed, we will say, in a case of Intermittent fever, the Index showing the temperature to have been 104°; (_B_) a thermometer with the Index at 95°.

The Index in a Clinical Thermometer is a small quantity of mercury separated by a bubble of air from the rest of the mercury; or, owing to the peculiar construction of the glass tube, without any air being present, a portion of the mercury separates itself from the bulk, and remains separated in the tube, as an Index. Upon placing the Thermometer in a favourable situation, in or against the body of a patient, owing to the amount of heat with which it there comes in contact, the mercury in the bulb expands, and the Index is pushed up to the highest point in the Thermometer that the heat of the body at that time is capable of causing, if the Thermometer is kept in contact with the body for the requisite time; and when the Thermometer is removed from its contact with the body, the mass of mercury suddenly cooling down, contracts, and returns into the bulb, the Index being left behind at the point to which the heat of the body had forced the mercury in the bulb to raise it; thus the Thermometer in Diagram A shows that in that instance the Index had been raised to 104° Fahrenheit and that that was the temperature of the body at that observation.

In commencing to take the temperature of a patient, first of all see that the Index is in the position as seen in Diagram _B_, not necessarily always as low as 95°, but at all events well under the arrow →, which marks off the mean normal temperature of any one in healthy viz., 98·4° Fahrenheit, as given in most English thermometers (98·6° as used on the Continent). The temperature of an infant or young child is frequently found to be 99° whilst in health.

Supposing a Thermometer is put into any one's hands, reading as at Diagram _A_ 104°, how is the Index to be replaced to the position it occupies in Diagram _B_? Hold the Thermometer by its upper end (the bulb being considered the lower end) then swing it round with your arm, suddenly stopping the arm with a jerk, this jerk causes the Index to fall towards the bulb, continue this, and after each jerk see how far the Index has fallen, when it has got well under the arrow →, the Thermometer for an ordinary case is ready for use.

When, however, one expects a low temperature, it is best to have the Index of the Thermometer at or under 95°.

How and when to apply the Thermometer. With grown up children and adults I have always found it more convenient to take the Temperature by placing the bulbous end of the Thermometer into the mouth under the tongue, keeping it there, with the mouth, shut, for the requisite time, the patient in the meanwhile breathing only through the nostrils; with infants the most convenient place is to put the Thermometer in the flexure of the thigh, laying one of the thighs somewhat across the other, but being careful not to allow the clothes to touch the Thermometer; some prefer to place it in the armpit, or axilla. This I have not found always as convenient as the other two localities; any of these, however, is good for the purpose. Use the one you may deem most convenient, but be careful to keep the clothes from coming into contact with the Thermometer.

Thermometers are now made with such a rapid action, that at the very longest they do not now require to be kept in position for more than three minutes.

Immediately after having made an observation note down the temperature, along with the time at which the observation was taken; having done so, and not before, wash the Thermometer, but _not with hot water_, _and then_ jerk down the Index; so that the Thermometer is ready for future use. If the reading is in any way a doubtful one, take another observation at once.

If there is any anxiety connected with the case, it is advisable to take an observation every three hours, so long as the patient is awake; _never disturb_ a patient during natural sleep for the purpose. Ordinarily take an observation two or three times during the day, but at set hours and at regular intervals, always noting the time.

Whenever the temperature of a patient is found to be below or above the _normal_ 98·4°, viz., the arrow-mark on the Thermometer, then watch the case, as one requiring care. If the temperature has fallen as low as 97°, or gone up to 100°, make up your mind that there is something wrong; be vigilant. But a falling temperature below 97° means danger from collapse, and a rising one reaching 105° is a dangerous fever heat. In the last two occurrences remedial agents require to be applied to at once, and medical assistance urgently asked for.

Along with each thermometric observation, it is advisable to count the pulse, and the number of respirations [the average number of pulsations in a minute of a healthy adult are about 72, and the number of respirations about 16. In _young_ children and _infants_ the number of pulsations and respirations are usually much higher than in the adult, and so irregular that to the non-professional their value alone in diagnosing disease may be considered as doubtful, other signs and symptoms require to be more carefully studied, and taken into consideration along with them, and the temperature] that occur during the minute (the latter is easily done by laying the open hand on the upper part of the abdomen, and counting the number of _rises_) noting these, along with the temperature, and the time. Such data, if taken carefully and at regular intervals of time, form an invaluable means for assisting the physician in his diagnosis.

EXAMPLE.

+-----------------------+---------+---------+---------+ | | May 17. | May 17. | May 17. | +-----------------------+---------+---------+---------+ |Time | 9 A.M. | 12 noon | 3 P.M. | |Temperature | 98·4° | 100° | 100° | |Number of Pulsations | 72 | 80 | 80 | |Number of Respirations | 16 | 20 | 20 | +-----------------------+---------+---------+---------+

AITCHISON.

[Footnote 5] _Medical Thermometry_, by Dr. C. A. Wunderlich, translated by W. Batherst Woodman, M.D. 1871, p. 6.