CONVOLVULUS PANDURATUS. 
181 
possessed as regards the therapeutic value of this article. It 
is known, however, to produce a decided impression upon the 
alimentary canal, followed by purgative effects. On this 
account, it has been employed by country practitioners as a 
substitute for jalap, but compared with this medicine its opera- 
tion is feeble; it is stated to resemble that of rhubarb. Dr. B. 
S. Barton, informs us that, without doubt, it is the Mecha- 
meck, or wild rhubarb of the Indians. It would seem also to 
possess diuretic powers, and has acquired some reputation as 
an antilithic. In cases of calculous concretions, its efficacy 
has been noticed by Dr. Harris, of New Jersey, " who found 
an infusion or decoction of the root very useful in his own 
person; he was persuaded that it enabled him to pass the 
calculous granules with greater facility." 
Affinities. — The family of Convolvulacese, or Bind Weed 
tribe, to which the plant under consideration belongs, is one 
of the most natural to be found in the whole list of those 
which have been brought under classification. The indivi- 
duals composing it, are so closely allied by botanical resem- 
blances, that no difficulty presents in determing their position, 
while, at the same time, a uniformity of chemical constitution 
is so evident in those which have been examined, that a simi- 
larity of medicinal property must follow as an ordinary result. 
To this but few opposing anomalies have presented. The 
active purgative principle of the family is the resinoid matter, 
which has been found abundantly in the root of the Ipomcea 
jalapa, Convolvulus scammonia, C. mechoacan, C. turpe- 
thum,C. scoparius&nd. from the foregoing analysis in that of the 
C. panduratus. A similar resin is also reported by Deslong- 
champs to exist in the C. soldanella, and C. althozoides. 
With the amount of the resin the activity diminishes or in- 
creases. The C. battatas, and C. edulis, in a cultivated state, 
are entirely free from it; the former is the common sweet potato. 
These constitute the sole exceptions. Much of the alteration, 
however, which these species undergo is no doubt due to soil 
and climate. In fact, so general is the resemblance, that, 
when speaking of this family, Murray observes, " no other 
