SEEDS AND FRUITS. 315 



to twenty feet high, having large oblong leaves, thia and 

 papery. The small flowers are followed by the elongated, 

 ribbed fruits, each containing fifty or more oUy seeds, 

 arranged in five vertical rows. The tree blooms almost 

 constantly ; the fruits are collected twice a year. The 

 almost colorless seeds when dried become reddish-brown ; 

 they are elliptical, slightly flattened, and exalbuminous ; 

 the cotyledons are of a deep brownish or violet color, 

 filled with drops of oil and grains of aleurone. The con- 

 stituents of the seeds are cocoa-butter, thirty-four to fifty- 

 six per cent. ; the alkaloid Theobromine, Avhich imparts the 

 bitter taste ; sugar, cellulose, starch, and albuminoids. The 

 seeds are used in the manufacture of Butter of Cocoa 

 (used in perfumery) and of Chocolate and Cocoa. The 

 seeds are roasted, then ground into a paste; to this are 

 added vanilla, sugar, etc., forming chocolate, or without 

 these various ingredients it is cocoa. 



314. The Mustard-plants, Sinapis nigra and S. alba 

 (family Ciiudferce), native annuals of Europe, have stems 

 three to six feet high, with lyrate, pinnate, or dentate, 

 petioled leaves. The flowers are yellow, the fruit is a 

 sUique, smooth, and with a four-sided beak, in case of S. 

 nigra ; hispid, and with an ensiform beak, in case of S. 

 alba; the seeds of the former are roundish, or elliptical, 

 and deep brown ; of the latter, large and yellow. Their 

 taste is at firet oUy, then burning ; the taste of the black 

 seed being the stronger. They contain three per cent, of 

 fixed oil, which is odorless and tasteless. The oil is 

 expressed from the seeds. Mvstard-seed has been used in 

 medicine very many years, being mentioned by Theo- 

 phrastus and by Galen. It is used externally as a cata- 

 plasm, and internally as a diuretic and irritant. The 

 pulverized seeds are also used as a condiment. 



