The following article, published in 1918, supports the theory that the ancient ancestors of the Binham Brassa (Balanta people) were Nilotic peoples who mixed with Bantu peoples who migrated from the Nile Valley during the Holocene about seven thousand years ago. Nilotic people, for the most part, did not use the poison ordeal ritual, but Bantu people did. In addition, the poison from the mansone, bourdane or tali tree (known to European botanists as Erythrophleum) is found along the ancient Balanta migration path from the Nile Valley to Lake Chad, to the Niger River and across to the Senegal River.
http://www.gospelstudies.org.uk/biblicalstudies/pdf/e-books/frazer/folk-lore_in_the_ot_frazer_vol03.pdf
