The basis and origin here is that they are the opposite of the good signs mentioned. Namely: the movement of the crisis occurs before the onset of the period of limit and maturation - Hippocrates calls such a crisis ahead of the curve, and you know the reason for its malignancy - it does not happen on a crisis day, and the pulse begins to fall and becomes smaller.
Know that if signs of crisis appear before the period of limit and ripening and they are followed by abundant emptying, then you should not be deluded by this, for this comes from the abundance of matter and is an expulsion from the weakness of nature without preparation. One should also not be deceived by the relief that the patient experiences without obvious emptying: the reason for this is the immobility of the matter, and not its good quality. Often, although matter matures, nature cannot expel it due to its weakness.
If several bad signs appear simultaneously, when, for example, maturation is absent or different from what it should be and other bad signs are observed, and the doctor sentences the patient to death, then such a sentence is based on the rapid or slow appearance of the symptoms preceding the crisis, which we have already mentioned. So, for example, if the signs are bad and there is a black sediment in the urine, etc., and all this takes place on the fourth day, then death comes on the seventh day or, since the reasons mentioned determine the earlier onset of death, on the sixth.