THE WONDERS OF VEGETATION. 51 



palm. But as to milk, we are accustomed to look 

 upon it as solely an animal product. Such are the 

 impressions which we have received from our infancy, 

 and this was the source of the astonishment which seized 

 us at the first sight of the cow-tree. 



In Caracas, South America, there grows upon the 

 dry face of a rock a tree the leaves of which are dry 

 and barklike ; its great roots penetrate with difficulty 

 into the earth. During many months of the year not a 

 shower moistens its foliage the branches appear dead 

 and withered, but when the trunk is pierced a sweet 

 and nourishing milk flows forth. The supply of the 

 liquid is most abundant at sunrise. At that hour the 

 blacks and the natives, furnished with large pitchers to 

 receive the milk, which is yellow and gradually thickens 

 on the surface, arrive at the cow-trees from all quar- 

 ters. Some drink their supply on the spot, others 

 carry it away to their children. We might fancy 

 that we beheld the family of a patriarch who is dis- 

 tributing the milk of his herd. 



The milk-yielding plants belong, mainly, to three 

 families of Euphorbiacese, UrticeaB and Apocynese, but 

 in the juice of almost all of these acrid and deleterious 

 elements are to be found, from which the milk of the 

 cow-tree is free. Still there are some species of Eu- 

 phorbia and Asclepias which also yield milk that is 

 sweet and harmless. Thus in the Canaries we find 

 the Tabaila (Euphorbia lalsamifera) mentioned by 

 Pliny as Ferula, and as giving out, when pressed, a 

 liquor agreeable to the taste ; at Ceylon is found a 

 lactiferous Asclepias, the milk of which is used when 



