THE WONDERS OF VEGETATION. 53 



modification as animal milk. A cream forms on the 

 surface which cannot easily be taken off; the milk boils 

 up and shows a tendency to run over from the vessel 

 which contains it. If the cream is removed as it 

 forms, and a steady heat is kept up, the milk gradu- 

 ally assumes the consistency of paste ; then appear upon 

 the surface oily rings, like those which come Jbo the 

 surface of cream that has been upon the fire for some 

 time. Finally, this fat part envelopes the whole of 

 the posset, which then diffuses an odor exactly similar 

 to that of roast beef. 



The tree is found chiefly in the valleys of Cauca- 

 gua, in the Cordilleras, near the sea-coast, and in the 

 vicinity of the lake of Valencia. At Caucagua the 

 natives name it the " Arbo de leche " (milk-tree), and 

 assert that they can tell by the color and the thickness 

 of the leaves which trees contain the juice in the great- 

 est abundance, precisely as the farmer tells by certain 

 marks the good qualities of a milch cow. 



In 1829, Smith, the traveller, while passing through 

 the woods of Guiana, made special search for the tree 

 which had been described by Humboldt, and inquired 

 of all the guides if they could tell him any thing of 

 such a tree. He had already met milk-giving plants, 

 but the bitter taste of their sap was utterly unlike 

 milk. One day finding himself in a little Indian vil- 

 lage near the first rapids of the River Demerary, he 

 heard reports of a tree called the hya-hya, whose milk, 

 it was said, was nourishing and agreeable to the taste. 

 Determined to ascertain the fact, the traveller sent an 

 Indian in search of one of these trees. The Indian 



