Abstract
The Yoruba tribe of West African negroes, inhabiting the southwestern portion of Nigeria, W. A., is numerically large, consisting, it is estimated, of 2,000,000 individuals. Its members are distingguished by the tribal mark of three parallel horizontal scars on each cheek. Though this tribal marking has been strictly adhered to in the past, the younger generations are not marking their children in all instances, especially in the more cosmopolitan city of Lagos. The presence of these distinguishing marks was used by us to establish the individual's Yoruban descent.
During 1926 samples of blood from 325 individuals of the Yoruba tribe were collected in 0.9 per cent saline containing 2 per cent sodium citrate. After centrifuging and washing, suspensions of the red cells in normal saline were tested for agglutinable properties with known Group I and Group II human sera. These sera, free from preservative, were brought from New York in hermetically sealed 1.0 cc. ampules, and were kept continuously on ice up to the time of use. The open slide method was employed, in which 1 drop of serum was mixed with 1 drop of a heavy suspension of red cells on a slide. The reactions were rapid, clear cut, and easily readable with the naked eye, although the microscope was used from time to time as a check.
Adopting the Jansky classification, the results were:
The bloods were obtained at the following cities:
Thanks are hereby expressed to Dr. G. G. Butler, Pathologist at the Colonial Hospital at Lagos; to Dr. A. B. W. Smart, Medical Officer of the Prison at Lagos; and to Miss Olive Edens, acting superintendent of the Baptist High School for Girls at Abeokuta, all of whom aided in procuring the required samples of blood.
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