32 THE UNIVERSE. 



colouring of certain rocks. According to Marcel de 

 Serre, rock-salt, which is sometimes tinged with red, only 

 owes its tint to the microscopic animals which lived in 

 the waters wherein it Avas formed. This savant also tells 

 US that cornelians owe their beautiful red colour to the 

 presence of Infusoria, a fact irrefragably proved by an 

 inspection of some of these stones, embedded in which the 

 skeletons of different animalcules can be discovered. 



CHAPTER III. 



FOSSIL MEAL AND THE EARTH-EATEKS. 



In several paints of the Avorld the dearth of sources of 

 food compels men to nourish themselves with certain kinds 

 of earth which possess a true nutritive power. 



Travellers are too unanimous on this point to allow of 

 our doubting it. The fact too was known at a far more 

 distant epoch than is generally supposed, for it is men- 

 tioned in the old and curious book of Naude in the defence 

 of the great men accused of magic. It is there said that 

 certain earths of the Valley of Hebron are good to eat. 



Towards the mouth of the Orinoco, the Ottomacs, at 

 certain seasons of the year, nourish themselves to a great 

 extent with a fat ferruginous clay, of which they consume 

 as much as a pound and a half a day. Spix and INIartius 

 say that a similar custom is found on the banks of the 

 Amazon; and those learned travellers relate that the 

 natives there eat this earth even when there is no lack of 

 more substantial food. We know also that an edible clay 



