Part of Sickness

Definition

The Part of Sickness is one of the Arabic Parts — calculated points, also called Lots — that classical and medieval medical astrologers used to look at where the body is vulnerable and at chronic illness. Dorotheus of Sidon's Carmen Astrologicum IV.IV.2 §§11-12 gives the standard formula, which he credits to "the ancient scholars" (an earlier Babylonian-Egyptian authority): by day, Asc + Mars − Saturn; by night, Asc + Saturn − Mars. The tradition holds several illness-related Lots; the Part's position, ruling planet, and aspects are read together with the 6th house and its ruler.

In Tradition

In Hellenistic and Arabic-Persian medical astrology, the Part of Sickness is the leading disease-significator for 6th-house matters — it sharpens the broader reading you already get from the 6th house and the Mars-Saturn pairing. The day/night reversal keeps the malefic logic intact: Saturn rules chronic constraint and decay, Mars rules sudden affliction and accident, and the formula flips so it stays aligned with whichever malefic dominates that birth. Bonatti and Lilly catalogue a cluster of disease Lots — sickness, accident, surgery — consulted together.

In Practice

You compute the Lot by formula, then read its sign, house, ruling planet, and aspects. That ruler's essential and accidental dignity (its inborn strength and its strength of placement), together with the condition of the 6th house and its ruler, signal how vulnerable the person's constitution is; the house of the Lot shows the life-context where illness surfaces; aspects from malefics intensify the affliction, aspects from benefics ease it. In horary practice for medical questions, the Lot is read alongside the birth Moon, the 6th cusp and its ruler, and the decumbiture Ascendant — the chart for the moment someone takes to their sickbed. As with all Arabic Parts, traditional practice tests several illness-related Lots side by side rather than leaning on one canonical formula.

Historical Origin

The Lot of chronic illness is recorded in Dorotheus of Sidon's Carmen Astrologicum Book IV Chapter IV.2 (1st century CE, surviving through Arabic transmission), which credits the formula to an earlier Babylonian-Egyptian authority. The doctrine passed through Sahl, Masha'allah, Abu Ma'shar, and 'Umar al-Tabari into the medieval Latin tradition, was set out formally in Bonatti's Liber Astronomiae (c. 1277), and was preserved for early-modern English horary by William Lilly's Christian Astrology (1647).

Further Reading