20 Original Communications. 
that being the time at which the pods are ripe ; they contain 
a portion of the active principle as well as the leaves ; it ap- 
pearing at this period to be most widely disseminated over 
the plant. It is mentioned by Rafinesque that American 
senna is more efficacious than that of Egypt ; it is however 
much inferior to the Alexandrian, requiring a larger quantity 
to produce similar effects. As most plants growing in dry 
and exposed situations, are more active than those growing 
in rich, moist soils, it is probable that the inferiority of the 
American senna to the imported, is owing to this cause ; and 
it might, under similar circumstances of growth, be equal to 
that in strength. It has been introduced into Europe: the 
first that reached there was sent from the state of Maryland, 
and hence its specific name. The leaves, as they occur in the 
shops, are packed in oblong cakes, as is usual with most 
plants derived from the Shakers. They are from one to two 
inches in length, and near half an inch in breadth, thin and 
pliable, of a pale green colour ; the odour is slightly analo- 
gous to that of imported senna, though by no means so nau- 
seous. Its effects on the system are similar to those produced 
by the imported. 
Its medical virtues are imparted to water by decoction or 
infusion, and to alcohol. A tincture may be formed with di- 
luted alcohol, which is, like the infusion, of a reddish brown 
colour. Alcohol and ether, digested on the powdered leaves, 
become of a deep olive green colour. The infusion and de- 
coction become turbid on exposure to the air, owing to the 
conversion of the extractive matter into apotheme. 
The medicine is best administered in the form of infusion ; 
the following formula will give a preparation equal in strength 
to that directed by the U. S. Pharmacopoeia, from the im- 
ported, and it may, under all circumstances, be substituted 
for that. Take of 
American senna, 1^ oz. 
Coriander seeds, bruised, 1 drachm. 
Boiling water, 1 pint, 
Macerate in a covered vessel for one hour, and strain. 
With a view of demonstrating the analogy existing be- 
