nerve fibres. It is to this action that the dryness of throat and 
mouth characteristic of belladonna poisoning is due. 
The natural alkaloid, 7-hyosecyamine and its d-isomeride resemble 
atropine (d/-hyoscyamine) qualitatively in action. . . . 
{ Hyoscine (scopolamine) | has an action similar to, but more tran- 
sitory than, that of atropine on the peripheral, cholergic, autonomic 
nervous system. Its action on the central nervous system is differ- 
ent. Generally it induces a feeling of fatigue and drowsiness pass- 
ing into sleep. In some cases there may be a preliminary stage of 
excitement, and with large doses excitement indistinguishable from 
that of atropine intoxication may occur. The respiratory centre is 
depressed from the start. The /-isomeride has the more powerful 
peripheral action, although the central action of both isomerides is 
the same (p. 106-7). 
Claus and Tyler (10) add that atropine applied locally 
causes a ‘“‘dullness or slight paralysis of the sensory 
nerves’, thus easing pain. This action probably relates 
to the frequent use of leaves in treating rheumatism. 
General statements such as these give a good indica- 
tion of the types of pharmacologic activity which proba- 
bly will be demonstrated in the tree Daturas, and suggest 
the basis for both their medicinal and psychotropic use 
by the Sibundoy. However, because the Sibundoy Da- 
turas are constant hosts to several viruses which may 
affect the cultivars differently, and because the Sibundoy 
have encountered greatly differing levels of toxicity, it 
seems very probable that an eventual understanding 
both of the biogenesis and of the pharmacologic activity 
of the Sibundoy Datura alkaloids will constitute a unique 
chapter in our increasing knowledge of the solanaceous 
tropane alkaloids. 
Key to Datura in the Valley of Sibundoy 
A. Exposed corolla mostly red, leaves soft-pubescent D. sanguinea 
a. Corolla tube yellow at the middle . . . . . cv. Guamuco 
aa. Corolla tube green or red at the middle, lacking 
Wellow entirely «§ < & 4s & # & @ ss 
AA. Corolla lacking red, leaves not soft-pubescent . . D2. candida 
[ 197 ] 
ev. Sangre 
