What is an alkaloid found in the Calabar bean, and the seed of Physostigma venenosum; physostigmine. It is used in ophthalmic surgery for its effect in contracting the pupil called?

eserine — An alkaloid found in the Calabar bean, and the seed of Physostigma venenosum; physostigmine. It is used in ophthalmic surgery for its effect in contracting the pupil. (Webster's 1913.)

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