Vincas or periwinkles: Old poison of Madagascar's ordeal trials

Vincas or periwinkles growing wild in a trail of Cape Florida state park in Key Biscayne - For photo licensing go here. 

The common Madagascar periwinkle (Vinca rosea or Catharanthus roseus) is pretty and also poisonous - all parts of the plant are toxic. So much, that it's said that in its native Madagascar the plant was used to create a poisonous beverage for ordeal trials before they switched to the tangena. 

Old books talk of these trials. One of them is, The story of Ida Pfeiffer and her travels in many lands. 

The government of Madagascar has always been Draconian in its severity, and the penalty exacted for almost every offence is blood. Some of the unfortunates are burned; others are hurled over a high rock; others buried alive; others scalded to death with boiling water; others killed with the spear; others sewn up alive in mats, and left to perish of hunger and corruption; and others beheaded. Recourse is not unfrequently had to poison, which is used as a kind of ordeal or test.  

The poisoning process takes place as follows:—

The material employed is obtained from the kernel of a fruit as large as a peach, called the Tanghinia venenifera. The lampi-tanghini, or person who administers the poison, announces to the accused the day on which the perilous dose is to be swallowed. For eight-and-forty hours before the prescribed time he is allowed to eat very little, and for the last twenty-four hours nothing at all. His friends accompany him to the poisoner’s house. There he undresses, and takes oath that he has had no recourse to magic.  The lampi-tanghini then scrapes away as much powder from the kernel with a knife as he judges necessary for the trial. Before administering the dose, he asks the accused if he confesses his crime; which the accused never does, because under any circumstances he would have to swallow the poison. The said poison is spread upon three little pieces of skin, each about an inch in size, cut from the back of a plump fowl. These he rolls together, and administers to the supposed culprit.

"In former days," says Madame Pfeiffer, "almost every person who was subjected to this ordeal died in great agony; but for the last ten years any one not condemned by the queen herself to take the tanghin, is allowed to make use of the following antidote. As soon as he has taken the poison, his friends make him drink rice-water in such quantities that his whole body sometimes swells visibly, and quick and violent vomiting is brought on. If the poisoned man be fortunate enough to get rid not only of the poison, but of the three little skins (which latter must be returned uninjured), he is declared innocent, and his relations carry him home in triumph, with songs and rejoicings. But if one of the pieces of skin should fail to reappear, or if it be at all injured, his life is forfeited, and he is executed with the spear, or by some other means."