Digestive damage follows damage to the lower part of the stomach or is due to a cause in food, or a cause depending on the immobility or movement of the body. As for the disease due to damage to the stomach, this may be a disorder of nature. The strongest disorder is coldness, and the weakest is warmth; A cold nature is more harmful to digestion than a hot one. As for dry or wet disorder of nature, both of them in most cases do not reach such a strength that due to them alone, digestive damage occurs when both other substances are balanced, unless the dry disorder causes thinness, and the wet disorder causes dropsy. With regard to the influence of rest and sleep or the opposite state on digestion and the resulting judgments about the digestion of food under such circumstances, the situation is as follows: food requires rest and sleep in order for digestion to be good. If instead there is movement or insomnia, then digestion is not completed. Heavy food stays in the stomach for a long time and is eventually digested or remains undigested or poorly digested. As for light food, if it is not digested, its time in undigested form does not last long, and when the stomach does not have the opportunity to digest it, it quickly spoils. A nutrient is either completely transformed into what it should be, thanks to perfect digestion, or it is transformed into what it should be, only to some extent and undergoes incomplete digestion. Then the body does not receive the required amount of nutrients from the amount of food that it is able to accept, and thinness occurs.
Or the food is not digested at all, and this is expressed in two ways: the food then either remains as it is, or turns into a substance foreign to the body and spoiled. This sometimes happens with any digestion, even with the third and fourth, and for this reason dropsy, cancer, herpes, erysipelas, bahak, baras and jarab arise. The fact is that the blood either does not then reach a maturity suitable for nature, so that the organs do not attract it to feed on it, and it rots and becomes fetid, or the organs attract the blood, but assimilating it to these organs is not good; if coarseness and warmth predominate in food, it turns black, and the black part of it sometimes becomes like resin. If the stomach does not absorb food at all, then it comes to “slippery intestines” and tympanic dropsy; however, this leads to hydrocele only if the stomach acts upon the food sufficiently to vaporize it, but does not digest it.
Know that indigestion, its weakness and in general its damage, if it is caused by any matter, can be treated better than damage caused by weak stomach strength and an established disorder of nature.