Indigo, cultivated for its rich blue dye, was grown on vast plantations and harvested by slaves. It was a source of great wealth for plantation owners, but is often thought to have caused serious health problems for the slaves who worked with it.

Further information on Indigo Plantations

 

Spanish moss (Tillandsia usneoides) is not a true moss, but an epiphytic flowering plant (one that lives on other plants).

Lourdes, a small town in southwest France, is an important centre of Catholicism, following a series of appearances by the Virgin Mary to 14-year-old Maria-Bernada Sobirós in 1858.  Maria-Bernada was later made Saint Marie-Bernarde Soubirous.

The reference to Arles is more puzzling as the French town is not associated with any significant vision.  One important pair of visionaries, however, were Paul Gauguin and Vincent Van Gogh, who spent nine weeks living and working together in Arles.  The paintings from that period strike many as the product of some kind of vision, although it seems unlikely that Catholic Rice (even in her atheist period) would have considered the artists saints.

Bloodletting was a common medical practice up to the late 1800s, intended to cure or prevent illnesses. It involved the withdrawal of blood, sometimes in large quantities, usually through puncturing a vein or by applying leeches. It was used to treat a wide variety of ailments, but generally left the patients in a worse condition than before.