TESTS FOR IMPORTANT MEDICINAL PREPARATIONS. 569 
paration in view of its supposed diuretic and diaphoretic 
effects, is disappointed, and obtains instead the, to some degree, 
opposite effect of so much alcohol. Hence this preparation 
also is gradually falling into disfavour and disuse. In view of 
the circumstances mentioned in connexion with these prepa- 
rations, and the like tendency in many others, it is well worth 
while for the profession to consider how far it is willing to 
sacrifice its valuable curative agents to the cupidity of manu- 
facturers. 
Chloroform . — When equal volumes of chloroform and colour- 
less concentrated sulphuric acid (the strong commercial oil 
of vitriol answers very well) are shaken together in a glass 
stoppered vial there should be no colour imparted to either 
liquid, or but a faint tinge of colour, after twelve hours’ 
standing together. Nor should there be any heat developed 
in the mixture at the time of shaking it first. Any particles 
of dust, or cork, or other organic matter that may have been 
in the vial used, or in the chloroform, will, by reaction of the 
acid, produce a tinge of colour in the acid or its separation 
from the chloroform, corresponding to the quantity of such 
particles present, and therefore in the application of the test 
care must be taken to avoid any such particles. Or if the 
acid be only faintly tinged at the end of twelve hours’ contact 
with the chloroform, it maybe attributed to some such colla- 
teral accidental cause. But, if at the end of twelve hours, or 
sooner, the acid becomes yellow, or brown, or any darker 
colour, it should be unhesitatingly rejected. If the mixture 
of acid and chloroform should become warm on shaking first, 
an admixture of alcohol would be indicated. One or two 
fluid drachms of chloroform spontaneously evaporated from 
a clean surface of glass or porcelain, or from a piece of dean 
unsized paper, should leave no odour after it. Commercial 
chloroform generally will turn the acid brown within two or 
three hours, and will often render it black and tarry-looking 
within two or three days, whilst with chemically pure 
chloroform there is absolutely no reaction wfithin many days. 
Calomel . — The most common and injurious contamination 
of calomel is corrosive sublimate, whereby its otherwise mild 
action is rendered irritant. This impurity is easily detected 
by shaking a drachm or two of the calomel in a test-tube 
with distilled water, and, when the water shall have become 
clear, adding a drop or two of liquor ammonia. If corrosive 
sublimate be present, the ammonia will precipitate it and 
render the water cloudy. 
Iodide of mercury — is often irritant and harsh in its action 
through contamination w T ith biniodide from faulty preparation. 
