§ 565. Effects.—Pelikan[594] has studied the effects of various saponins on frogs. One to two drops of a saturated watery solution of saponin applied subcutaneously to the leg, caused, in from five to six minutes, great weakness, accompanied by a loss of sensibility; but strong mechanical, chemical, or electrical stimuli applied to the foot excited reflex action, for the ischiatic nerve still retained its functions. Nevertheless, from the commencement, the excitability of the poisoned muscles was much weakened, and just before death quite disappeared. Section of the ischiatic nerve delayed the phenomena. Curarine did not seem to have any effect on the poisonous action. A concentrated solution applied to the heart of a frog soon arrests its beats, but weaker doses first excite, and then retard.[595]
[594] Berl. klin. Wochschr., 36, 186.
[595] J. Hoppe, Nervenwirkung der Heilmittel, H. 4, 37.
The author has studied the general action of saponin on kittens, insects, and infusoria. Small doses, such as from 13 to 32 mgrms. (1⁄5 to 1⁄2 grain), were injected beneath the loose skin of the back of the neck of a kitten, when there were immediate symptoms of local pain. In from five to ten minutes the respiration notably quickened, and the animal fell into a lethargic state, with signs of general muscular weakness; just before death the breathing became very rapid, and there were all the signs of asphyxia. The pathological appearances after death were fulness in the right side of the heart, and intense congestion of the intestinal canal, the stomach generally being perfectly normal in appearance, and the kidneys and other organs healthy. The least fatal dose for a kitten seems to be 13 mgrms., or ·04 grm. to a kilogram.[596]
[596] The action of saponin when applied in concentrated solution to flies is that of an intense irritant. There is protrusion of the sucker, and progressive paralysis. The common infusoria live for some time in dilute solutions of saponin—this is also true of some of the higher forms; for example, a Cyclops quadricornis seemed in no way affected by a 2 per cent. solution.
§ 566. Action on Man.—The effects of saponin on man have been but little studied; it has been administered by the mouth in doses of from ·1 to ·2 grm., and in those doses seems to have distinct physiological effects. There is increased mucous secretion, and a feeling of nausea; but neither diaphoresis nor diuresis has been observed. From the foregoing study it may be predicated that 2·6 grms. (40 grains), if administered subcutaneously to an adult, would endanger life. The symptoms would be great muscular prostration, weakness of the heart’s action, and probably diarrhœa. In fatal cases, some signs of an irritant or inflammatory action on the mucous membranes of the stomach and intestines would be probable.