PLANT ANALYSIS AS AN APPLIED SCIENCE 183 
in large wire cages, and then are run into an immense boiler 
or “extractor.” A heavy door is shut securely, and about 
300 barrels of light petroleum are pumped in by an engine, 
and heat is applied by means of a steam coil, until a pressure 
of 100 pounds to the square inch has been obtained. 
The object of this high pressure is to break or crush the 
glands, which contain the valuable principle called lupulin, 
this being taken up by the hot petroleum. The process is so 
managed that there is very little waste of menstruum, and 
the hop extract is readily separated; the petroleum-ether 
being used over and over again. One pound of this extract 
represents about twelve pounds of choice hops, and it has 
a great advantage over the hop itself, as it will keep for an 
indefinite time; whereas at the end of two years the hop is 
useless. 
Hop-resin, 1 or bitter, was discovered from the chemical 
analysis of a plant, and it illustrates to what practical ends a 
fact derived from this source may be applied. The solubility 
of hop-resin in petroleum-ether is availed of also in the ex¬ 
amination of beer. 2 
Vegetable wax is found on the surfaces of leaves, on the 
stem, and the berries of plants, and is obtained from many 
sources. The commercial supply comes from certain species 
of the palm-tree family in considerable quantities. Carnaiiba 
wax is from a large Brazilian palm. Myrica, or myrtle wax, 
comes from the berries of an American and Mexican plant, 
Myrica red] er a of the Myricacece family, and Japan wax is 
obtained from Rhus succedaneum. 
Vegetable wax 3 is principally used in the manufacture of 
candles, but on account of its greater dryness, it breaks much 
more readily than animal wax; hence, if animal wax is mixed 
in small proportions with vegetable wax, it answers very well. 
1 Lermer, Vierteljahresschr. j. prakt. Pharm. ,x ii, 504, 1863; Bissell, Amer. 
Jour. Pharm., xlix, 582, 1877; Griessmayer, Ber. d. d. Chem. Ges., xi, 292, 
1878; Isleib, Archiv, d. Pharm. (3), xvi, 345, 1880; Cech, Zeitschr. f. Anal. 
Chem., xx, 180, 1881. 
2 Griessmayer. 
3 Matieres Premieres Organiques. Par Pennetier, p. 771. 
