ALCOHOLIC PREPARATIONS OF THE PHARMACOPffilA. 47 
ART. XIII.— ON THE ACETOUS FERMENTATION OF^ SOME 
OF THE ALCOHOLIC PREPARATIONS OF THE PHAR- 
MACOPOEIA. 
By Mr, William Bastick. 
In all the works on Materia Medica and Pharmacy 
which I have examined, where the subject is alluded to at 
all, it is stated that the tinctures of the Pharmacopoeia are 
very stable preparations, and that the only deterioration 
which takes place in them is that caused by the evaporation 
of the spirit, producing, in consequence, either a more con- 
centrated tincture, or precipitating a portion of the mate- 
rials held in solution. That the above statement falls far 
short of the real facts is well known by all Pharmaceutists, 
from the circumstance that most of the tinctures made 
with proof spirit undergo a gradual change, which 
ultimately ends in rendering them comparatively inert and 
worthless. 
With a view to ascertain what was the general nature of 
the change to which these alcoholic preparations were 
liable, portions of various ones were kept many months in 
the ordinary circumstances in which they would be placed 
by their consumption in a Druggists' shop, such as being in 
bottles half-filled in a temperature varying from 60 to 80 
degrees of Fahrenheit, and occasionally admitting fresh 
air. 
After a lapse of time, most of them, on examination by 
the proper tests, were found to have undergone the acetous 
fermentation in a greater or lesser degree — the alcohol 
having been gradually converted into acetic acid. The 
tinctures were generally diminished in colour and taste, 
and contained a precipitate, a portion of which was re- 
