REVIEW— COGSWELL ON IODINE. 
291 
or indolent tumours and enlargements ; and he has found even 
osseous swellings, splints and spavins, in time, to become dimi- 
nished by continual inunction. After some daily perfrications, an 
exudation of yellowish concretion appears upon the surface, which 
at the same time becomes tender or sore from the application. 
When this happens the inunction had better be discontinued, to 
be renewed at some future time, as soon as the effects shall have 
passed away. 
There appears to be a prodigious quantity of adulterated iodide 
of potassium on sale, and, consequently, it behoves practitioners 
who are in the habit of prescribing it to take care that they are 
not imposed upon by their druggists. The adulterating ingredi- 
ent is carbonate of potash. “At a discussion of the London 
Medical Society, having reference to Dr. Elliotson’s practice of 
administering this compound in doses cf two drachms , Mr. 
Pereira stated his belief that but one house in London sold it pure.” 
Such being the fallacy our medical practice is exposed to, it 
becomes our duty, ere we prescribe it, to subject this medicinal 
to tests of some sort. Dr. Traill has suggested an easy method 
of detecting sophistication. “Tincture of iodine, added to the 
suspected compound, loses its colour if the carbonate be present. 
Mr. Pereira proposed to immerse one of the crystals in lime- 
water, when the presence of carbonic acid will be indicated bv 
the fluid growing milky.” We must also bear in mind, that 
“ the iodide of potassium should not be prescribed along with the 
salts of copper, silver, lead, and mercury.” “ The chief use that 
has been made of this compound among the (medical) profes- 
sion at large, is that of a solvent for iodine; or, when applied 
alone externally, the internal use of iodine has been very com- 
monly conjoined with it.” 
“From certain facts stated by Drs. Zuik and Guirdner, iodine 
would seem to undergo absorption through the cuticle; not only 
did tumours in distant situations disappear, during the practice 
of spreading some of the ointment on particular surfaces, but the 
last named gentleman has even witnessed the supervention of 
gastric pain and copious bilious diarrhoea.” 
The following experiment made by Mr. Cogswell shews that 
the action of iodine, subcutaneously applied, is not confined to 
“local irritation,” but “extends over the system.” 
“Three drachms of hydriodate of potash, dissolved in half an 
ounce of tepid water, were injected beneath the skin of the back of 
a strong common-sized terrier dog. The animal, for two or three 
minutes, seemed to be in great pain, but after this recovered, and 
took his food as if nothing had happened. Towards evening he 
was evidently in low spirits, though still inclined for food. In the 
