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SELECTED ARTICLES. 
illustrate what is here stated. A man affected with palsy 
took every evening gradually increasing doses of a strychnia 
less pure than the average, till at length one evening the dose 
was directed to be increased from two-thirds to three-fourths 
of a grain in two pills. At the same time the sample of the 
medicine supplied by the apothecary was changed for one 
almost of snowy whiteness, and consequently far purer. 
Through some lucky whim the patient took only one pill. 
In the night time he was attacked with violent tetanic con- 
vulsions, protracted spasms of the extremities, severe locked- 
jaw, violent opisthotonos, spasmodic fixing of the chest, and 
all the other formidable symptoms of poisoning with this 
alkaloid; in which state he continued for several hours. From 
all we know of the effects of strychnia, there can be little 
doubt that had he taken both pills the issue would have been 
fatal. 
6. Apt illustrations may also be taken from vegetable drugs 
of a compound nature, into which impurities may be intro- 
duced accidentally, or by design, more easily perhaps than 
into any other description of medicines, and where also the 
detection of them is sometimes exceedingly difficult. Under 
this head I shall take as examples three of the most familiar 
and most valuable articles of the Materia Medica, namely, 
gamboge, scammony, and opium. Gamboge is one of those 
purgatives, to which some physicians entertain a dislike on 
account of its supposed irregularity and violence of action. 
But this notion has always appeared to me founded on pre- 
judice; for after extensive trial of it, often without any adjunct 
except inert powders to facilitate fine division, it has appeared 
to me equally manageable, safe, and uniform in effect, with 
any other active cathartic. Various causes may be assigned 
for its occasional irregularity of action. Whether its sophis- 
tication is one cause, 1 know not; but the frequency and 
extent of the adulterations of gamboge are sufficient to account 
for the variations complained of. I have been led to pay 
particular attention to this subject, — which, by the way, is 
