Henry St. Clair Whitehead (1882-1932) was an American clergyman, teacher and a writer of horror fiction and fantasy, best known for his creepy tales of magic and voodoo.
'Passing of a God' is a voodoo story set in the West Indies which tells of an American who presents himself at the hospital in Port au Prince with a huge tumour in his abdomen.
The surgeon there agrees to operate...but discovers there is something very peculiar and sinister about the tumour...and about the story his patient tells him about how he came to visit the hospital.