A clinical thermometer is a short, triangular, hollow, glass shaft. At one end a bulb holds mercury. When a thermometer is put into the mouth the mercury expands through the hollow shaft as the temperature registers. The shaft is marked into degrees and parts of a degree so that the recording may be easily read. The slight constriction in the glass between the bulb and the shaft holds the mercury fixed after it is taken out of the patients mouth. Force the mercury into the bulb by a gentle snap of the wrist-while the shaft is held between the thumb and finger.
There is a very close relationship between temperature and pulse. The pulse will increase from five to ten beats with one degree elevation in temperature. The rise in temperature during an illness is the bodies way of fighting the cause of the disease-the bacteria, and repairing the damage which the bacteria have done. To produce any degree of heat, there must be oxygen. The body breathes in oxygen and the blood carries it to the cells of the body. This accounts for the increase both in pulse and respiration when there is an elevation of temperature.
There may be exceptions, of course; people do not always react to disease as you might expect them to do. There are variations of pulse for which you must watch: a bounding pulse strikes your finger tips with considerable force. Look for this in people who have diseases of the arteries. Pulse might have a second, weaker beat as part of a double beat. Look for this in people with low blood pressure. Thready pulse is rapid and thin. It disappears if you press on the artery with any pressure.
