A stone taken out of a swallow, said to be good against melancholy and periodical disorder. It was placed in a yellow linen cloth and tied about the neck to cure fever. Stones are sometimes found in birds and other mammals, especially in ducts and hollow organs; they are usually pathological concretions known as calculi.
"Chelidonius." Encyclopedia of Occultism and Parapsychology. . Encyclopedia.com. (September 20, 2018). http://www.encyclopedia.com/science/encyclopedias-almanacs-transcripts-and-maps/chelidonius
"Chelidonius." Encyclopedia of Occultism and Parapsychology. . Retrieved September 20, 2018 from Encyclopedia.com: http://www.encyclopedia.com/science/encyclopedias-almanacs-transcripts-and-maps/chelidonius