PHYSOSTIGMA 237 



four in 1860. It belongs to the great natural order 

 Leguminosae, tribe Phaseolese. It is a curious fact that 

 these poisonous seeds are so closely related, botanically, 

 to the ordinary edible bean of our gardens, that the 

 structural difference resides mainly in the stigma. 

 The genus at present (1897) consists of three species, 

 Physostigma venenosum, Balf; Physostigma cylindro- 

 sperma, Holmes, and a recently described species, Phy- 

 sostigma mesoponticum, Taubert, all from tropical 

 Africa. Physostigma venenosum is one of the numerous 

 woody climbers that inhabit the tropical forests of 

 Africa, sometimes reaching the length of fifty feet, with 

 a stem two inches in diameter. The leaves are pinnately 

 trifoliate, and in size and shape very closely approxi- 

 mate the leaves of the common "Lima bean" of our 

 gardens. The fruit is a thick brown pod, each con- 

 taining two or three large seeds familiar to us as "Cala- 

 bar beans." 



HISTORY. The Calabar or ordeal bean seems to be 

 confined in its habitat to a limited area only, around the 

 Gulf of Guinea, and particularly about the mouth of the 

 old Calabar River, hence its common name. The first 

 report we have from that region concerning the use of 

 this seed as an ordeal poison is by Dr. W. F. Daniell, 

 who in 1846 ("Natives of Old Calibar," Edirib. New 

 Philos. Journ., 1846, p. 316), states that among the 

 natives, "persons suspected of a crime are forced to 

 swallow a deadly poison made from the seeds of an 

 aquatic leguminous plant which rapidly destroys life." 

 The seed is called esere by the natives, which accounts 

 for one of the alkaloids of this bean being named eserine. 

 We are informed that the Calabar bean as an ordeal is 

 administered in various quantities. Less than half a 



