400 CSF electrophoreses were performed on Black West Africans (Ivory Coast) with inflammatory infections of the nervous system. In the normal state, the CSF of the Black African contains a higher concentration of gamma-globulins than the European (15.8% compared to 8--10%). This study permits us to confirm indirectly the classical idea of the extreme rarity of MS in tropical areas: an increase in the gamma-globulins of the CSF has been shown in 22% of the cases and the two principal responsible infections are trypanosomiasis (57.3%) and SSPE (16.8%). The oligoclonal distribution by various authors in trypanosomiases was not found. On the contrary, a nonclonal aspect of gamma-zone was constantly found (49/50). It is possible that the differences are in accordance with the different evolutionary phases of the disease, and that the oligoclonal distribution is a marker of the autoimmune state of the disease.