Africa (at the time we lost a portion of our collections), both assured us, that the Otomacs never mix their clay cakes with crocodile’s fat, and we heard nothing in Uruana of the admixture of flour. The earth which we brought with us, and which was chemically investigated by M. Vauquelin, is quite pure and unmixed. May not Gumilla, by confounding heterogeneous facts, have intended to allude to a preparation of bread from the long pod of a species of Inga? as this fruit is certainly buried in the earth, in order to hasten its decomposition. It appears to me especially remarkable, that the Otomacs should not lose their health by eating so much earth. Has this tribe been habituated for generations to this stimulus? In all tropical countries men exhibit a wonderful and almost irresistible desire to devour earth, not the so-called alkaline or calcareous earth, for the purpose of neutralizing acidity, but unctuous, strong-smelling clay. It is often found necessary to shut children up in order to prevent their running into the open air to devour earth after recent rain. The Indian women who are engaged on the river Magdalena, in the small village of Banco, in turning earthenware pots, continually fill their mouths with large lumps of clay, as I have frequently observed, much to my surprise.[HL] Wolves eat earth, especially clay, during winter. It would be very important, in a physiological point of view, to examine the excrements of animals and men that eat earth. Individuals of all other tribes, excepting the Otomacs, lose their health if they yield to this singular propensity for eating clay. In the mission of San Borja we found the child of an Indian woman, which, according to the statement of its mother, would hardly eat anything but earth. It was, however, much emaciated, and looked like a mere skeleton. Why is it that in the temperate and cold zones this morbid eagerness for eating earth is so much less frequently manifested, and is indeed limited almost entirely to children and pregnant women, whilst it would appear to be indigenous to the tropical lands of every quarter of the earth? In Guinea the negroes eat a yellowish earth, which they call _caouac_; and when they are carried as slaves to the West Indies they even endeavour there to procure for themselves some similar species of food, maintaining that the eating of earth is perfectly harmless in their African home. The _caouac_ of the American islands, however, deranges the health of the slaves who partake of it; for which reason the eating of earth was long since forbidden in the West Indies, notwithstanding which a species of red or yellowish tuff (_un tuf rouge jaunâtre_) was secretly sold in the public market of Martinique in the year 1751.