IMPURITIES IN MEDICINES, &C. 
109 
been informed that in France, when the artificial barilla is de- 
signed for the production of carbonate of soda, that means are 
always employed thoroughly to remove the sulphuret, and 
hence that French carbonate, whether made from native ba- 
rilla or artificial is always freer from this contamination. 
From the same source I learn that the artificial barilla made 
in this country is all designed for the use of soap manufac- 
turers, and that therefore the same care is not observed in its 
preparation; the wants of that class requiring the alkali un- 
combined, render but little preparation necessary in the manu- 
facture of the barilla, and it is of course an object with the 
manufacturer to furnish the article at its lowest price. 
This consideration should not prevail with our profession, 
and care should therefore be taken to avoid the unpleasant re- 
sults, which might follow the employment of carbonate of 
soda containing sulphuret of soda. 
With regard to the tests necessary to detect its presence, 
I should think the disagreeable odour itself would be suffi- 
cient; but at all events, the presence of any sulphuret may be 
made manifest with a soluble salt of silver or lead. 
Spt. Etheris Nitrici. In preparing some of this ether a 
short time since, the mixture was inflamed, and burned for 
several minutes within the retort. The nitrate of potassa and 
sulphuric acid had been mixed, and when about an ounce of 
alcohol was poured in upon them, an explosion took place 
with sufficient force to throw a small glass funnel, then in the 
mouth of the retort, some distance; the mixture within blazed 
up and burned for some minutes, as I have above stated. I 
have never noticed any effect approaching this before, and 
merely note it as a caution to others who may be employed 
in making this preparation. 
