Du Mez—The Galenical Oleoresins. 
1065 
The rhizomes as they are found on the market occur in a 
variety of forms characteristic of the source from which they 
are obtained. In view of this fact, the Pharmacopoeia recog¬ 
nizes six different commercial varieties, namely: Jamaica ginger, 
African ginger, Calcutta ginger, Calicut ginger, Cochin 
ginger and Japanese ginger. These commercial forms differ 
to a considerable extent, not only through natural causes, but 
also through a difference in the conditions under which they are 
harvested and prepared for the market. 
As a rule the rhizomes are dug after the stems have withered, 
January or February, when one or more years old. Experience 
has shown the oleoresin content to be the greatest at this period 
of the year . 1 They are then washed in boiling water to pre¬ 
vent germination, dried rapidly in the sun, and as such con¬ 
stitute, what is known as black, coated, or unscraped ginger. 
In other cases, after treatment with boiling water, a part or 
the whole of the epidermis is removed, the rhizomes dried, and 
bleached with sulphur fumes, chlorinated lime, milk of lime or 
gypsum. This constitutes the so-called, white, uncoated, 
scraped, race or hard ginger . 2 
In commenting on the relative values of these various forms 
of ginger in the preparation of the oleoresin, it should be stated, 
first of all, that the yield of oleoresin is influenced to the largest 
extent by habitat, African ginger giving the maximum yield . 3 
Secondly, the extent to which the rhizomes have been decorticated 
is an important factor, as the outer corky layer contains none 
of the oleoresinous material. These factors will be more fully 
discussed under yield. To what degree, if at all, the process 
of so-called bleaching effects the yield or quality of oleoresin 
does not become apparent from the literature. It is thought, 
however, that a heavy coating of gypsum, for instance, would 
tend to considerably reduce the percentage of oleoresin ob¬ 
tainable. 
1 Hooper, Fharm. Journ. (1912), 89, p. 391. 
2 Culbreth, Mat. Med. and Pharmacol. (1917), p. 130. 
3 See reference under “Yield of oleoresin”. 
