INTRODUCTION. 



xxxiii 



able for their large seeds, which contain a con- 

 siderable quantity of starch, and consequently 

 possess nutritive properties. It is, however, 

 asserted that the Buck-eye, or American Horse- 

 chestnut, is a deadly poison, a bitter narcotic 

 principle being contained in the root, leaves, and 

 fruit. Potash also enters into the composition of 

 the seeds, and in some instances to such an extent, 

 that they may be used as a substitute for soap. 



The Horse-chestnuts are included by some bo- 

 tanists in the more extensive order of Soap worts, 

 of which the following are the most remarkable 

 examples. The Soap-tree, Sapindus saponaria, 

 produces fruit which lathers freely in water and 

 is used in the West Indies as a substitute for 

 soap. A pound of the fruit, it is said, will cleanse 

 more linen than sixty pounds of soap. The dis- 

 tilled water of the flowers of the soapy Cupania 

 is used by Negro-women as a lotion for the face. 



Other allied genera are very poisonous : a spe- 

 cies of Paulinia, a Brazilian tree, has bark, 

 leaves, and fruit, which abound in an acrid prin- 

 ciple, and the blacks prepare from them an insidi- 

 ous poison which slowly but certainly destroys 

 life. Several others possess intoxicating proper- 

 ties, and some are medicinal. From the seeds of 

 Paulinia sorhilis a food called Guarana bread is 

 prepared by the savages of Brazil, which is sold 

 all over the country as an indispensable requisite 

 for travellers, and a cure for many disorders. The 

 genus Nephelium furnishes many of the most deli- 

 cious fruits of the Indian Archipelago. The 

 Snake-nut tree, described by Schomburgk, is a 

 native of Demerara, and is so called from the 

 curved embryo of the seed which, when in a state 



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