The reasoning about these things is in some way connected with the reasoning about the tumors mentioned above. We say: in an organ, decomposition and decay arise from causes that either spoil the animal pneuma located in it, or prevent it from reaching a given organ, or combine both of these qualities; such, for example, are poisons, hot and cold, opposite in substance to animal pneuma. Or it comes from malignant, creeping tumors, pimples and ulcers, the substance of which is poisonous, and also from ulcers, in relation to which mistakes are made in the treatment. So, sometimes by mistake they pour oil into deep-lying ulcers, and the meat rots, or they cool hot tumors too much, and the nature of the organ deteriorates.
As for obstacles, these are blockages. Such blockages can be accidental, external, when, for example, some organ is pulled tightly at the very base; if this continues for a long time, then the organ rots, since the access of the animal pneuma or the access of the force spreading in the heart as a result of breathing and passing on to the pneuma contained in this organ is blocked; then the nature of the organ deteriorates and it dies.
And sometimes blockages occur in the body itself. This is, for example, a tumor - hot, malignant, stable, large, with thick matter; it blocks the paths and passages for breathing, thanks to which the animal pneuma lives, and when they are all blocked, this also spoils nature.
If such phenomena occur at the beginning and the sensitivity of what is sensitive is not impaired, this is called gangrene, especially if the tumor was initially phlegmon, and if the tumor has become so strong that it has deprived the sensitive organ of sensitivity, for the meat and what is adjacent to it, even to the bone, rotted at the beginning or after the tumor, then this is called syphaculus. Gangrene sometimes turns into syphaculus, or rather, this is even the path to it. All this happens in meat, but it also happens in bones and other places.
When damage begins to spread in an organ and the area around the rotting part swells, this whole phenomenon is generally called corrosive gangrene, and the state of the rotting part of the organ is called dying. If the tumor matter were not thick, it would not linger and would rush out.