The following are the true facts, which I verified. The Otomacs, over months, eat three quarters of a pound of slightly baked clay daily. Their health is not affected. They moisten the clay to swallow it. It was not possible to find out what other vegetable or animal matter the Indians ate at the same time; but it is clear that the sensation of a full stomach came from the clay, and not from whatever else they might eat Everywhere in the torrid zone I noticed women, children, even full-grown men, show a great desire to swallow earth. Not an alkaline or calcareous earth to neutralize acid juices, but a fat, oily clay with a strong smell. They often have to tie children's hands to prevent them from eating earth when it stops raining. In the village of Banco, on the Magdalena, I saw Indian women potters continually swallowing great lumps of clay. They were not pregnant, and said, 'Earth is food that does not harm us. It could be asked why this mania for eating earth is so rare in the cool, temperate zones, compared to the Tropics; and why in Europe it is confined to pregnant women and sick children.