1908-9.] Stropliantlius sarmentosus : Pharmacological Action. 415 
XXV. — Strophanthus sarmentosus : its Pharmacological Action 
and its Use as an Arrow Poison. By Sir Thomas R. Fraser, 
M.D., F.R.S.S. L. & E., Professor of Materia Medica in the University 
of Edinburgh ; and Alister T. Mackenzie, M.A., M.B., Ch.B., 
Carnegie Research Scholar. 
(Abstract.) 
An extract of the seeds of Strophanthus sarmentosus appears to be an 
important ingredient of the arrow-poison of Nigeria and other parts of 
West Africa. While some of the other ingredients of this arrow-poison 
may possess toxic power, others of them have little or no toxicity and are 
introduced into the arrow-poison with the object, apparently, of rendering 
it more viscous and adhesive or with a superstitious intention. 
The seeds contain a glucosidal active principle as well as a large 
quantity of inert oil and other substances soluble in ether. 
In order to determine the nature of the pharmacological action, an 
alcohol extract freed from substances soluble in ether was used. Its 
minimum-lethal dose by subcutaneous injection per kilogram of animal 
was found to be, for the frog, 0*0035 gram ; for the rat, 0*3 gram ; for the 
rabbit, 0*0015 gram ; and for the cat, 0*002 gram ; and, by intravenous 
injection, for the rabbit, 0*0012 gram. 
The minimum -lethal dose is, therefore, by subcutaneous injection, 
almost the same for rabbits and cats, and for frogs it is twice as large, and 
for rats 200 times as large as for rabbits. 
The predominating effects are those produced upon the heart and the 
skeletal muscles. 
Under the influence of S. sarmentosus , shortening of skeletal muscles 
is produced, and, later, fibrillary twitches become conspicuous. When 
these twitches have disappeared, the contraction of the muscle under 
stimulation is more gradual, the amount of contraction is less, and the 
relaxation of the muscle is slower than before ; stronger stimuli are 
needed to produce contraction ; and, soon, the strongest direct electrical 
stimulation fails to cause contraction of the muscle. At this time the 
muscle is pale, rigid and acid in reaction. 
The effects of the extract on the heart are the most important of those 
