298 
STRYCHNOS NUX VOMICA. 
until the desired effect is produced ; tlie medicine must then be dis- 
continued to avoid accidents, and if it has been suspended for some 
days, it is necessary to recommence with the smaller doses, gradually 
increasing them as before. Sometimes it is necessary to increase 
the dose to twenty-four or thirty grains in the day, before the 
tetanic convulsions are produced ; but generally from four to si\ 
grains will be found sufficient,* When it is wished to produce only 
the slow effects, from a grain to a grain and a half in the day is sutfi- 
cient. M. Magendie has also. prepared a tincture for this purpose, 
with the dry extract of the Nux Vomica and alcohol. 
Strychnine. We have said that M. Pelletier discovered the 
existence of two alkaHne substances. Strychnine and Brucine, 
in the Nux Vomica, and to which, but particularly the former, it owes 
its active properties: these alkalies are likewise found in the Strych- 
flos Ignalii and Strychnos Colubrina. Strychnine is prepared as fol- 
lows: — " Add a solution of liquid subacetate of lead to a solution in 
water of alcoholic extract of Nux Vomica, until no more precipitate 
is thrown down ; separate the 4ead by sulphuretted hydrogen ; fil- 
trate it, and boil with magnesia, which will unite with the acetic 
aeid, and precipitate the Strychnine. Wash the precipitate in cold 
water ; redissolve it in alcohol, to separate the excess of magnesia, 
and by evaporating the alcohol the Strychnine is obtained in a state 
of purity : if not perfectly white, it must be redissolved in acetic or 
hydrochloric acid, and reprecipitated by means of magnesia." f 
When slowly crystalUzed, it appears under the form of microscopical 
crystals, forming four-sided prisms, terminated by pyramids, with 
four flattened or depressed faces. Crystallized rapidly, it is white 
and granular ; it is insupportably bitter to the taste, has no smell, is 
not changed by exposure to the air, is neither fusible nor volatile ; 
is decomposed by a degree of heat inferior to that which destroys 
most vegetable substances. Exposed to the naked fire, it swells, 
becomes black, and gives out an empyreumatic oil, a little water, 
acetic acid, carbonic acid gas, and carbonated hydrogen; it is 
scarcely soluble in water, requiring 2500 parts of boiling water. The 
principal character of Strychnine consists in its forming neutral salts 
when united with acids; these salts are crystallizable, and for the 
most part soluble, and are much more active than the simple sub- 
• M. Magendie says, " It is better to give the pills in the evening, because nigtt is 
the best time for observing the phenomenon which we wish to produce, 
t Magendie'* FormaUire. 
