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 recifera 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. f. prakt. Pharm., xii, 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. /. Anal. 



Chem., xx, 180, 1881. 



2 Griessmayer. 



3 Matures Premieres Organiques. Par Pennetier, p. 771. 



