1. Dryness is the predominant qi of autumn. Excessive dryness leads to the pathogenic factor known as “dryness evil” (zao xie). There are two types of dryness evil: warm dryness and cool dryness. Early autumn often sees residual summer heat, leading to warm dryness, while late autumn, approaching winter, tends to exhibit cool dryness. Internal dryness is often caused by excessive sweating, which depletes body fluids and blood.
(1) Characteristics and Pathogenic Features of Dryness Evil
① Dryness is characterized by its desiccating nature, which easily injures body fluids. Symptoms include dryness of the mouth and nose, dry skin and hair, dry eyes without moisture, hard stools, short and dark urine, thirst, and dry cough without phlegm.
② Dryness easily injures the lungs. As dryness is the predominant qi of autumn (associated with the metal element), it often enters through the mouth and nose, thus easily harming the lungs. This can lead to symptoms such as dry cough with little phlegm, phlegm that is difficult to expectorate, or even blood-streaked phlegm, along with wheezing and chest pain.
(2) Common Dryness Syndromes:
① External Dryness. External dryness can be classified into warm dryness and cool dryness.
Cool dryness is a syndrome characterized by cold dryness. Symptoms include fever, chills, absence of sweating, dry skin, dry mouth and tongue, dry nasal passages, and dry cough without phlegm. The tongue coating is thin, white, and dry, with a wiry pulse. Treatment should focus on dispersing the lungs, releasing the exterior, and moistening dryness.
Warm dryness is characterized by heat. Symptoms include fever, slight sweating, unproductive dry cough, thirst, hard stools, dry and red throat, red tongue, thin yellow coating, and a rapid, large pulse. Treatment should involve using acrid-cool herbs to release the exterior and clear the lungs while moistening dryness.
② Internal Dryness.
Internal dryness often results from the invasion of dryness evil, accumulation of heat in the five organs damaging body fluids, chronic wasting diseases leading to yin deficiency, excessive vomiting or diarrhea, profuse sweating, significant bleeding, or the use of sweating-inducing, harsh purging, and warm-dryness herbs that deplete yin and blood. Symptoms include body weakness, dry mouth, and dry nose. Treatment should focus on nourishing yin and moistening dryness. For intestinal dryness due to insufficient fluids, treatment should aim to moisten the intestines and relieve constipation; if lung dryness is present, clear the lungs and moisten dryness.
2. Heat (Fire Evil), heat, fire, summer heat, and warmth are all manifestations of excessive yang. All four are yang evils with fundamentally similar properties, hence they are often collectively referred to as fire heat, summer heat, and warm heat.
However, the four have distinctions. In terms of severity, warmth can transform into heat, and heat can generate fire; thus, warmth is a gradual increase of heat, while fire represents the extreme of heat. Additionally, fire is most prevalent in summer, particularly during the four solar terms from the vernal equinox to the beginning of summer. Summer heat primarily occurs between the summer solstice and the beginning of autumn, showing clear seasonal characteristics, while fire heat does not have obvious seasonal patterns and can also be influenced by high-temperature environments.
Warm evil refers to a category of external evils with warm and hot properties, including wind-heat, summer-heat, damp-heat, and dry-heat among the six excesses, as well as pestilential qi and epidemic toxins; fire can also arise internally, known as internal fire. This often results from the stagnation of the six excess evils transforming into fire, leading to dysfunction of the organs and a pathological state of hyperactivity, such as liver fire, heart fire, and stomach fire. Fire can be classified into excess fire and deficient fire. Excess fire arises from external fire (heat) evils invading the body, causing excessive yang heat; deficient fire results from organ deficiency, prolonged illness leading to malnourishment, and depletion of body fluids.
(1) Characteristics and Pathogenic Features of Heat Evil
① Heat is a yang evil characterized by its inflammatory nature. Yang is associated with agitation and ascension, and heat rises and inflames, thus heat is considered a yang evil. Pathological conditions caused by fire heat often present with high fever, aversion to heat, thirst, sweating, and a rapid pulse. Due to its inflammatory nature, it often disturbs the spirit, leading to agitation and confusion, with symptoms commonly seen in the head and face.
② Heat (Fire) easily depletes qi and injures body fluids. Fire heat evil can force fluids to leak out, leading to depletion of yin fluids. Symptoms include dry tongue with little moisture, thirst with a preference for drinking, short and red urine, hard stools, and even symptoms of dehydration such as sunken eyes.
③ Heat (Fire) easily generates wind and stirs blood. The fire heat evil can easily cause internal wind in the liver, known as “extreme heat generates wind.” At the same time, fire heat accelerates blood circulation, forcing blood to move erratically, leading to various bleeding disorders.
④ Heat (Fire) easily generates swelling and toxins. Fire evil can enter the blood level, accumulating locally, leading to putrefaction and pus formation, accompanied by local redness, swelling, heat, and pain, and even leading to abscesses and ulceration.
⑤ Heat easily disturbs the heart and spirit. Fire corresponds to heart qi, and fire heat most easily disturbs the heart and spirit, leading to agitation and restlessness.
⑥ Rapid transmission of changes. As Ye Tianshi stated in “On Warm Heat,” “Warm evils transform into heat most rapidly.” This indicates that the onset of the disease is sudden, with rapid changes and diverse manifestations.
(2) Common Fire Heat Syndromes
① Excess Fire. External heat evils or other external evils enter the body and transform into heat. Symptoms include high fever, excessive thirst, wheezing, red and dark urine, cough, nasal discharge of purulent mucus, bleeding, rashes, constipation, or foul-smelling diarrhea, red tongue with yellow coating, rapid and forceful pulse, and even confusion or convulsions. Treatment should focus on clearing heat and draining fire.
② Deficient Fire. This refers to internal fire, often resulting from dietary imbalance, prolonged illness leading to body deficiency, and insufficient yin fluids, which fail to restrain yang. Symptoms include thin body, dry hair, thirst without much desire to drink, night sweats, spermatorrhea, slightly red tongue, and weak rapid pulse. (Excerpt from Traditional Chinese Veterinary Medicine)