Abstract

The sting of the live Manchurian scorpion in frogs produces a primary spasm and twitching of the muscles and increased reflex excitability, which are followed by paralysis. In guinea-pigs such bites produce powerful epileptic convulsions and collapse with death of the animal by respiratory paralysis.

2. An extract of the dried, expressed juice of the venom glands of the scorpion injected into a frog produces the same symptoms as those following a bite by the living animal.

3. Muscular twitchings and spasmodic contractions of the muscles are of peripheral origin due to the direct action of the poison on the motor nerve endings, and when the excised muscle is immersed in the toxic extract the motor nerve endings lose their excitability.

4. The concentrated extracts of the venom glands produce an irritation of sensory nerve endings.

5. The toxic extract has no definite action on the nerve trunks or on striated muscle itself; the minimal fatal dose of the extract for frogs varies from 0.05 to 0.1 mgm. per gram weight. I am deeply indebted to Dr. David I. Macht of the Johns Hopkins University for completing this paper in English.