the discovery of the uele was schweinfurth's greatest geographical achievement, though he did much to elucidate the hydrography of the bahr-el-ghazal system. of greater importance were the very considerable additions he made to the knowledge of the inhabitants and of the flora and fauna of central africa. he described in detail the cannibalistic practices of the mangbetu, and his discovery of the pygmy aka people settled conclusively the question as to the existence of dwarf races in tropical africa. unfortunately, a december 1870 fire in his camp destroyed nearly all that he had collected. he returned to khartoum in july 1871 and published an account of the expedition, under the title of "im herzen von afrika" (leipzig, 1874; english edition, the heart of africa, 1873, new ed. 1878).