Let us now proceed to a detailed discussion of each of the listed general provisions. Here is the first reasoning. We say: as for the general position about natures, hot, cold, dry and wet natures give rise to suffering, according to what we taught in the general principles, although, as you already know, the dry nature has little ability to cause pain, and the wet nature , since it is moist, does not cause pain, unless there is moist matter present, which causes pain due to the formation of vapors and the creation of winds that produce a discontinuity. Hot-dry and cold-dry natures cause pain with these two qualities, as well as with movements that break continuity. Hot-moist and cold-moist natures cause pain only because they are hot or cold, and do not amuse that they are wet, with the exception of the case mentioned above.
The cause of a hot nature can be either hot matter, blood, or bile, or complex, sharp, burning matter, which acts by its quality, or its cause can be hot wind and steam, or warming bodily or mental movements, the varieties of which you are already familiar with from General Fundamentals. The cause of a hot nature can also be contact with fire, sunburn, consumption of hot food or medicine, or the proximity and complicity of the brain with heated organs. The reasons for a cold nature causing headaches are the opposite of those mentioned above. You can list them yourself.
The cause of dry nature is either external influences that dry by resorption and burning, such as burning winds and hot medicinal dressings, or influences that cause hardening, natural or collateral, occurring suddenly or not suddenly; they prevent nutrients from penetrating into the head, and the organs of the head dry out, as the absorption of moisture from the outside stops, and their own moisture is absorbed. These can be effects that dry from the inside by resorption or evacuation, or due to their inherent drying force, and from the fact that the food is dry or slightly moist, as well as the proximity or complicity of a dried organ, excessive mental and physical movements that dry by evacuation and resorption, copulation, expulsion of urine, bleeding, increased exercise and various types of bowel movements. This also includes emptying of organs that are not organs of the head, with which the head participates, for example, general emptying of the entire body or private emptying of one of the organs. Such emptying can also affect the organs of the head, for example, with a runny nose, catarrh, nosebleeds and various discharges caused by nasal medications that cause sneezing and rinsing. The cause of the dry nature of the brain can also be a cessation of the influx of moist matter into the brain, even if not caused by emptying, for example, due to fasting, refusal of food or lack of it.