52 THE WONDERS OF VEGETATION. 



cow's milk cannot be had, while the leaves are used 

 in cooking such food as is elsewhere prepared with 

 cow's milk. 



This natural vegetable milk offers besides other 

 points of affinity and resemblance to natural milk. 

 Thus, placed in the open air, in a short time a yellow- 

 ish, thick membrane appears on the surface, not unlike 

 the little skin that forms on milk, and this continues 

 to thicken and is taken off, to be kept under the name 

 of cheese often for a week. Nature, however, also 

 takes to churning herself occasionally. On the banks 

 of the Niger, the natives gather 'their butter directly 

 from a tree (Pentadesma ~butyracea) and sell it in 

 their markets. It is said that the kings of Dahomey, 

 fearing its value as an article of export, and thus as a 

 means of bringing the land into relations with more 

 civilized countries, have ordered it to be extermina- 

 ted ! It is annually burnt by royal decree it annu- 

 ally springs up again defying the decrees of the cruel 

 sovereigns. 



Although many kinds of lactiferous plants furnish 

 caoutchouc, not a trace of it is found in the product 

 of the cow-tree; and the cheese of which we have 

 spoken are not very different from our own. In 

 chemical analysis the tree milk bears a close affinity 

 to animal milk ; the butter is represented in the veg- 

 etable milk by a beautiful and abundant wax, caseine, 

 by a substance not unlike the fibrine of blood, and the 

 serum by a watery liquid containing a little sugar 

 and a small percentage of the salt of magnesia. 

 Placed over the fire vegetable milk undergoes the same 



