( 209 ) 
The cured leaves are sold either in the entire condition or 
powdered, and afford the chief beverage of Paraguay and 
many parts of the Argentine Republic and southern Brazil. 
They contain much less caffeine than ordinary tea, and 
have a very different flavor, but are used for the same pur- 
pose and produce the same effect. Paraguay-tea is ex- 
tremely cheap as compared with ordinary tea, and brief 
use makes people equally well satisfied with it. In the 
block of cases devoted to beverages may be found choco- 
late, which is derived from the seed of the chocolate tree 
(Theobroma). The collection shows the chocolate fruits, 
the principal commercial varieties of the seeds, aaieaaed 
and roasted, nibs of different degrees of ees germs, 
cocoa-liquor, cocoa-butter, cocoa-cake, and the same ground 
into ‘‘breakfast’’-cocoa, with several varieties of confect- 
tioners’ chocolate, as put up for the market. 
Miscellaneous Specimens. Case 50.— In this case may 
be seen the substances used in the manufacture of insect- 
powders and related substances, and soap. Soaps are 
made from fats or fixed oils, acted upon while hot by a 
caustic alkali, or “lye,” ordinarily by boiling the two to- 
gether. The fat consists of one or more acids, variously 
combined with glycerin. The alkali takes away the 
acids, uniting with them to form soap, the glycerin being 
set free. Either animal or vegetable fats can be em- 
ployed, the characters of the soaps differing more or less 
with the particular fat used. The character of the alkali, 
such as soda or potash, also modifies the quality of the 
soap. The soap may contain free alkali, free fat, free 
glycerin, or water, in variable proportions, all of which 
will modify its quality. Official soap (that used in medi- 
cine) should not float on water and should contain not 
more than 36 per cent. of water. 
Fixed Oils and Volatile Oils. Cases 51 to 56.—The 
volatile oils form a large series, and in their manufacture 
various parts of the plants are used; for example, roots are 
used to make the oils of lovage-root, elecampane, and 
