196 
ON IMPORTATIONS OP IODINE. 
refinement of Scottish iodine has been effected. This, in- 
deed corresponds with the assertion of Dr. Christison, made 
several years ago, that " until within a recent period, he 
had not met with any British iodine which did not contain 
from fifteen to twenty per cent, of moisture."* Dr. Pereira 
says (Mat. Med., vol i., 225.) "The iodine of commerce is 
always adulterated with variable proportions of water. An 
ounce, if very moist, may contain a drachm, or perhaps even 
a drachm and a half of water." These observations seem 
to show not only that the refinement of iodine is of recent 
introduction, but that the quality of the ordinary article has 
been much improved within late years, since it is believed 
that the average proportion of water to be found in the 
iodine of commerce at present, is far less than that above 
given. Certainly no example has occurred of any importa- 
tion of this article to Philadelphia since the operation of 
the drug law, with any thing like this amount of moisture ; 
the greatest amount thus far having been but five per cent. 
These two qualities of iodine — the ordinary, or " commer- 
cial," and the anhydrous or M resublimed" — form two very 
different and well defined varieties; the former occurring 
in irregular or amorphous lumps (with a frequent tendency 
to minute crystallization) having a dull bluish, greyish, or 
dark lead color, and characterized by its tendency to adhere 
to the bottle or containing vessel ; the latter occurring in 
moderately small and uniform scales or micaceous crys- 
tals, of a blue or somewhat steel like color, and with a clean 
metallic lustre. The first contains an amount of water 
ranging from one to ten, or perhaps even fifteen per cent; 
the last is found varying from a condition of perfect dryness 
to one with a half or one per cent of moisture. 
In the mercantile world, the term " Iodine" is still ap- 
propriated to the former variety, and wherever it is used in 
the market, or quoted in the London prices-current, it is 
* U. S. Dispensatory, p. 391. 
