ON THE ADULTERATION OF DRUGS. 
119 
ten per cent. It is an intentional adulteration; at least there 
is no circumstance in the processes for preparing iodide of 
potassium which can lead to its accidental introduction, except 
in small quantity. 
2. Iodine itself is another instance. Various impregnations 
of iodine have been indicated by authors, such as with oxide 
of manganese, brick dust, and other substances of a fixed nature; 
which, however, I have never met with throughout a long 
train of investigations. But there is another impurity, at pre- 
sent seldom wanting in British iodine, and which has not yet 
been publicly noticed. This is with water. It is probably 
not very easy to prevent a certain impregnation with water. 
But nothing except gross carelessness or fraud will account 
for^he presence of fifteen per cent., which I have separated, or 
for twenty per cent., which I am informed by M. Robiquet of 
Paris is not unfrequently found in the British iodine imported 
into France. Perhaps this amount of impurity is not of very 
material consequence to medical practice, the variation of the 
dose by a fifth part being probably not so important as many 
would have us think. The admixture, however, is not the 
less a fraud, — a fraud, I may add, which, according to M. Ro- 
biquet, has of late greatly reduced the demand in France for 
iodine of British manufacture. 
3. Another good example is the spirit of nitric ether, a 
medicine of much value, and in most extensive use. I have 
not myself made any experiments upon its adulterations. 
But the subject may be equally well illustrated from the evi- 
dence delivered in 1834, by Mr. Cooper, lecturer on chemistry 
in London, before the Medical Education Committee of the 
House of Commons. Mr. Cooper, while travelling between 
Bath and London, happened to call for an acquaintance, a 
chemist and a druggist in one of the intermediate towns. 
During his visit, the travelling member of a wholesale house in 
London called in pursuit of his occupation, and among other 
things offered for sale the spirit of nitric ether. His customer 
asked him its price, to which he replied that he had it of 
