THE ANIMAL KINGDOM. 



33 



is sold in the markets of Bolivia; and lastly, Gliddon assures 

 us that there are a tolerably large number of earth-eating 

 tribes in North America, especially among the negroes 

 spread through the forests of Carolina and Florida. 



Natux-alists, struck Avith these accounts, were anxious 

 to make out the composition of these edible earths, and 



18. Microscopic view of Infusoria in Mountain-meal of Ebsdoi-f.^ 



to their astonishment discovered that some of them were 

 nothing else than species of tripohs, or clays, containing 

 a considerable number of fresh-water Infusoria or micro- 

 scopic shells; so that we may assume that these alimentary 



^ In Europe the most celebrated deposits of mountain-meal are those of Lap- 

 land, of Degernji and Lollhagysyou in Sweden, of Ebsdorf in the Lunenburg 

 Heath, and of Santafiora in Tuscany. Smaller deposits are found in Greece, 

 Hungary, Bohemia, France, and elsewhere. I myself discovered one in 1846 at 

 Lonl6 in South Portugal. Many of these aecnmulations of niouutain-meal are of 

 great importance to man, being mixed with common meal and used as food, 



