106 MEANS FOR. DETERMINING THE PURITY OF DRUGS, ETC. 
on it, i the additional trouble which these precautions require, 
should not be withheld. There are persons who, in using the cod 
liver oil, feel disapyointed that a single bottle or two has not 
wrought the changes they so earnestly desire, and give up its use. 
Such persons should be advised not to waste their money ; for 
unless (even in cases where the alterative and nutritive effects of 
the oil are strongly indicated,) its use is persevered in for a con- 
siderable length of time, and in doses by no means homoeopathic, it 
will be in vain to expect the excellent results which have been 
derived from its curative power in the hospitals as well as in pri- 
vate practice ; results greatly more attainable if the patient is not 
subjected to the constantly recurring disgust and nausea, from 
ill made and badly kept oil. 
ON THE MEANS FOR DETERMINING THE PURITY OF CERTAIN 
CHEMICALS AND DRUGS, AND FOR DETECTING ADULTERA- 
TIONS. 
(Continued from page 3.) 
[A large part of the article on Iodine has been taken from ob- 
servations by Dr. Herzog, of Germany, published in the Pharmaceu- 
tical Journal, Dec. i860, and Central Blatt.— Editor.] 
Iodine as met with in commerce, is presented in two forms, 
viz: in well defined dry crystals, having a metallic lustre and blueish 
black color, as "resublimed" iodine ; and as a dark iron grey sub- 
stance having the appearance of unoxidized iron filings, more or 
less moist, cohering together in lumps and adhering to the sides of 
the bottle, called " commercial iodine," or simply iodine.* 
The impurities which have been found in iodine, either acci- 
dental or designed, are quite numerous, but the British product, which 
is that most largely used in this country, does not appear to be so 
frequently the subject of adulteration as that in Continental com- 
merce. The substances which have been noticed in iodine by dif- 
ferent writers and chemists are, watery chloride of magnesium, clilo- 
*See a paper by Alfred B. Taylor, late Drug Inspector for this port, vol. 
xxii.pp. 193. 
