ON THE PHYSIOLOGICAL ACTION OF 

 CASCA BARK. 



In conjunction with Walter Pye. 



(Reprinted from Si. Bartholomew's Hospital Reports, 1876, vol. xii.) 



The practice of subjecting persons suspected of crime or 

 witchcraft to an ordeal by poison prevails very extensively 

 along the western coast of Africa. The poison employed is 

 not the same along the whole coast-line. In Calabar, which 

 lies about the middle, the natives employ the bean of the 

 Fhysostigma venenosum, or, as it is generally called, the Calabar 

 bean. To the north of Calabar, in Sierra Leone, and to the 

 south, in Anji^ola, the favourite ordeal poison is not a fruit, 

 but a bark, which bears in different districts the names of 

 " doom," " gidu," and " sassy," " saucy," " cassa," or " casca." This 

 bark is obtained from the Erytkrophlcum Gu'inense, which, like 

 the Physostigma venenosum, belongs to the natural order Zegii- 

 minosce. The bark is of a brownish-red colour, is in pieces 

 about 8 inches long, 4 broad, and between J and J thick. 

 When treated with water it yields a browni?h-red infusion. 



There are two ways in which it is employed by the natives. 

 One is to make the suspected person fast for several hours, and 

 then to give him a few grains of rice and some infusion of the 

 bark. If he vomits all the grains of rice and is not purged, he 

 is said to be innocent ; but if he is purged, he is pronounced 

 guilty The other way is to bend both ends of several boughs 

 of trees into the ground so as to form a long archway, through 

 which the accused walks in a stooping position after a dose of 

 the infusion has been administered. If he is able to walk 

 through without stumbling, he is considered to be innocent; 

 but if he stumbles, he is said to be guilty and at once de- 

 spatched. The chief effects of the poison by which the inno- 

 cence or guilt of the accused are decided are thus vomiting, 



