Relative Properties - Yin and Yang
The Physiology of Chinese medicine holds that the human body's life is the result of the balance of yin and yang. Yin is the inner and negative principles, and yang, outer and positive. The key reason why there is sickness is because the two aspects lose their harmony. Seen from the recovery mechanism of organs, yang functions to protect from outer harm, and yin is the inner base to store and provide energy for its counterpart.
Observation indicates that doctors directly watch the outward appearance to know a patient's condition. As the exterior and interior corresponds immediately, when the inner organs run wrongly, it will be reflected through skin pallor, tongue, the facial sensory organs and some excrement.
Auscultation and olfaction is a way for doctors to collect messages through hearing the sound and smelling the odor. This is another reference for diagnosis.
Interrogation suggests that doctors question the patient and his relatives, so as to know the symptoms, evolution of the disease and previous treatments.
The taking of the pulse and palpation refer that doctors noting the pulse condition of patients on the radial artery, and then to know the inner change of symptom. Doctors believe that when the organic function is normal, the pulse, frequency, and intension of pulse will be relatively stable, and when not, variant.