1074 Wisconsin Academy of Sciences, Arts, and Letters. 
fluid with a somewhat camphoraceous odor and an aromatic, but 
not a pungent taste. It is laevogyrate (-25 to 50°) and has a 
specific gravity of 0.875 to 0.886. It is soluble in strong alcohol, 
petroleum ether, carbon disulphide, benzene, turpentine and 
glacial acetic acid. The principal constituent of the oil, a 
sesquiterpene, gingerene or zingiberene, (C 15 H 24 ) was first 
definitely described by von Soden and Rojahn 5 in 1900. Accord¬ 
ing to Semmler and Becker, 6 it is a monocyclic butadiene having 
the following structure: 
The former investigators also identified d-camphene and phellan- 
drene 7 in the lower boiling fractions. In addition to these hy¬ 
drocarbons, Schimmel & Company 8 have reported the presence 
of citral, cineol, borneol and probably geraniol, and Dodge 9 the 
presence of an aldehyde of the probable formula, n-C 9 H 19 CHO. 
The volatile oil has been found to be present in the rhizomes 
in varying quantities depending on their age before harvesting, 
the methods of curing and their geographical source. 10 Ac- 
5 Pharm. Ztg. (1900), 45, p. 414. 
6 Ber. d. deutsch. chem. Gesell. (1913), 46, p. 1814. 
7 Schimmel & Co. Semi-Ann. Rep. (1905), II, p. 38. 
8 Fhellandrene and d-camphene were identified in the oil by Bertram and 
Walbaum in 1894. Journ. f. prakt. Chem. (1894), 49, p. 18. 
9 Chem. Abs. (1912), 6, 3, p. 2976; Orig. Com. 8th Intern. Congr. Appl. 
Chem. 6 p. 77. 
10 Gane reports the presence of volatile oil in ginger as follows: Jamaica 
0.64 per cent., Cochin 1.35 per cent., African 1.615 per cent., Fijian 1.45 per 
cent. Fharm. Journ. (1892), 51, p. 802. 
Thresh obtained 0.75 per cent, of oil from Jamaica ginger, 1.35 per cent, 
from Cochin and 1.61 per cent, from African. Pharm. Journ. (1879), 39, 
p.l. 191. 
Haensel states that he obtained only 1.072 per cent, of volatile oil from 
Jamaica ginger, whereas other sorts yielded from 2 to 3 per cent. Pharm. 
Ztg. (1903), 48, p. 58. 
Bennet found 0.20 to 0.90 per cent, of oil in Jamaica ginger, Pharm. Journ. 
(1901), 66, p. 522. 
Reich gives the following as the volatile oil content of various sorts of 
