Results (Table I). Relaxation of the membrane was observed with 2 (10 and 30 mg/kg) and 3 (10 mg/kg) and persisted up to 54 hr with the large dose of 2. By compari-son, a greater degree and more prolonged duration of relaxation was produced by smaller doses of guanethidine 12. None of the compounds caused mydriasis. Compound 1 had no noticeable effect on the nictitating membrane in doses up to 30 mg/kg.
