Today, July 20th, is Moon Day! To commemorate the day humans first walked on the moon in 1969, the Dittrick Museum looks at how centuries of scholars considered the movements of the moon and planets as having a great impact on health.

Athanasius Kircher, a 17th-century polymath priest, created an astrological chart know as a “Sciathericon” in his treatise on optics and light called Ars Magna Lucis et Umbrae (1671). This chart (Fig. 2) connected the zodiac with parts of human anatomy, types of health conditions, and the medications that could be used to treat these bodily complaints.

For example, the man in the Sciathericon stands with his right foot on the moon with a dotted line connecting his foot to “Podagra” or gout. Kircher suggests practitioners use “Intybus” or chicory to treat gout. At this time, physicians considered gout to occur most frequently in the Spring, or under the astrological sign of Pisces. Kircher’s Renaissance contemporaries frequently wrote about the co-occurrence of gout attacks with the full moon and the vernal equinox. Rather than allowing human complaints to be random, these charts functioned like clocks, ordering the observed illnesses and behaviors to correspond with regular planetary movements.

Fig. 3: The Moon and Lunar Cycle from Ars Magna Lucis et Umbrae, 1671.

Like Kircher, Nicholas Culpeper, a botanist and physician, looked to the heavens to understand human health. The frontispiece of Culpeper’s Last Legacy, a posthumous publication from 1676, shows the author with a crystal, a skull, and celestial globe, displaying the interrelatedness of astrology and the body in 17th-century medicine.

Culpeper’s system of medicine involved indexing herbs by the astronomical bodies governing them. If a physician knew the planet ruling a particular part of human anatomy and causing disease, treatment with herbs of the opposite planet could cure the affliction. For example, Culpeper writes that the moon is the antipathy of Saturn. Thus, moon-governed herbs like white saxifrage, a small white-flowering plant (No. 167 in Fig. 5) can cure diseases of the Saturn-ruled veins, like blockages and poisonings.

Eighteenth century physicians continued to look for connections between health and the position of the moon. British physician with the East India Company, Francis Balfour published A Treatise on the Influence of the Moon in Fevers in 1784. Balfour considered the time three days before a full moon to three days after the moon begins to wane to be a critical time for fever-diseases.

Although these findings came from his work in Bengal, India, Balfour extrapolated that all fever diseases function “in a similar manner in every inhibited quarter of the Globe; and consequently, a similar attention to it is a matter of general importance in the practice of Medicine” (p. 41).

Richard Meade, Royal Physician to King George II, also examined the link between the moon and medicine. Meade writes in A Treatise Concerning the Influence of the Sun and Moon upon Human Bodies and the Diseases thereby Produced (1748) that “it is most certain that epidemic fevers are caused by some noxious qualities of our atmosphere; and therefore it seems reasonable to suppose that such changes as produce those effects may happen in it in all seasons by the influence of the moon” (p. 68).

Meade incorporated the growing literature on gravity and tides into his medical arguments. He postulated that when the moon is closest to the Earth, the gravitational pull felt by oceans is also exerted on the atmosphere and a human’s circulatory system. By drawing on physics, Meade provided a mechanistic explanation of health fluctuations.

According to Meade, the twice daily occurrence of a closer moon causes regular swelling of the blood vessels. Additionally, conditions like plague frequently erupted during the new and full moons (when the lunar gravitational pull causes the highest barometric pressure) and grow worse during the tides. Meade’s work sought to order the seemingly random outbreaks of epidemics based on atmospheric variables. This research kept with contemporary miasma theory before information about plague-causing bacteria became available.

Today’s lunar holiday commemorates human’s intelligence, strength and determination to achieve previously unreachable goals. Meanwhile, this post recounted how centuries of researchers looked up and worried about how the moon’s position and proximity to our planet could, like clockwork, make us weak, cure ailments, or bring chaos and death. However, there is a similarity between the astronauts of the 20th and 21st centuries and the authors highlighted here. They sought to reveal the unknown facts of the universe and make clear our place in it. We celebrate them all today.