This is Lilly’s chart example from p. 286. As we know, he became a doctor several years after having finished his Christian Astrology, so medicine was an important matter to him and his chapter on this argument is the most detailed of the entire book.
In this question, the querent was a doctor himself. Lilly does not give details about the man, but he was presumably already sick when he came to the consultation and wanted to have some clarification about what exactly he was suffering.
Here is the chart:
Lilly gives a first glance at the chart an sees, that the AC is afflicted by the Northern and Southern Scale, Alpha Librae (Zubenelgenubi, 14°50’ Libra) and Beta Librae (Zubenelschamali 15°17’ Libra). Their actual positions are 15°05′ and 19°22′ Scorpio. Lilly refers to them as chelae, a denomination which goes back to a time, when Libra still didn’t exist as a separate constellation. The Northern and Southerns Scales were then simply the claws (chelae) of the ancient Scorpius, which had a much wider extension than nowadays.
According to Ebertin, Zubenelgenubi was malefic, while Zubenelschamali was benefic, but in a general sense, nobody likes to stay between the claws of a Scorpio, and thus their presence in the AC shows Lilly, that there was a problem linked to the querent’s health (1st house). The poor man was in the middle of a pair of scissors.
In previous chapters, Lilly had given a checklist, how to see if a person was ill:
- Check the 1st house, the 6th house and the house the Moon is in for the presence of a planet which is retrograde, combust or slow in motion and in square or opposition with the lord of the 4th, 8th or 12th.
- A planet in the AC or a planet in its proper domicile indicates problems linked to the head.
- Also check for the planetary significations in the signs (for example, Saturn in Cancer describes problems with the reins or stomach).
Lilly gives on p. 119 a table showing the association between the planets and the parts of the body. Since every planet in its proper sign rules the head, I reorganized his table accordingly (shown below). 
As we see, in Lilly’s example chart,
- There is no planet in the 1st house, but we have to consider Mars L1 in Leo, which points to the heart.
- Malefic Saturn is in the 6th
- The Moon is in Aquarius, not afflicted
Since Saturn is in his fall and in the 6th house of illness, he is the most afflicted planet. Lilly analyses his position as shown in the table above and concludes, that the illness is in the head, breast, heart and stomach.
Turning back to the chart, Lilly observed the AC ruler lately separated from a dexter square of Saturn, which confirms the initial delineation.
What caused the disease?
As we have seen, Saturn is the principal significator of the illness. He is in his own terms, and the Moon is applying to him by sextile. The Moon is in his house and aspecting Saturn by sextile. Remember that every planet is associated with a temperament. (See my article on the humors here).
- Melancholy (Saturn)
- Choler (Mars)
- Sanguine (Jupiter) and
- Phlegm (Moon/Venus)
Saturn nature is cold and dry, and his function is to conserve, to store. But when he is afflicted, he reduces and obstructs. This is why Lilly states, the illness is coming from “melancholic obstruction” in the head and breast.
- Mars (choler) is in the terms of Saturn (melancholy).
- The Moon applies to a square with the Sun, which is also in the terms of Mars (choler)
So we see a mixture of choler and melancholy.
Lilly describes his client to be very sick
With great pain in his head, very silent, dull and melancholy, slept very little, had a very dry cough and complained of great weakness and pain in the breast and the heart. His complexion between yellow and white and there was an inclination to the jaundice, he had besides a lingering consumption and great weariness all over him in every joint.
The Moon (natural significator of the bladder) is in an airy sign, which describes a swollen or inflated organ. In Aquarius, she describes the genitals.
Since Scorpio is ascending, a water sign which also describes the bladder, the man had difficulty to urine, due to stones in the bladder (Moon sextile Saturn= obstructions viz. stones).
Will the disease be long or short?
- Saturn is the author of the disease. Since he is ponderous and slow, his nature shows a long illness.
- The angles of the chart are in fixed signs.
- Moon and Sun are in fixed signs
- The luminaries are in square aspect
- The luminaries are in the terms of the malefics
- The Lord of the 6th is in a fixed sign
- The antiscion of Mars (28°01′ ) Taurus is close to the Sun
The man died on August 14th, 1645, nearly 3 months after the question. The time frame seems to be indicated by the Moon, only 3° apart from changing her sign, which indicates a change in the querent’s status.
 Ebertin-Hoffmann, Fixed Stars and their interpretation, Ebertin Verlag, 1971
 The content of my table is the same as in his, I only changes the sequence, to make the logic easier to understand.
 A dexter square is san aspect against the order of the signs, so Saturn in Aries is dexter from Mars in Leo. A dexter aspect is considered stronger than a sinister aspect.
 Compare Nicholas Culpeper, Richard Saunders and William Lilly