For instance, King's American Dispensatory states in the entry on belladonna: "Belladonna and opium appear to exert antagonistic influences, especially as regards their action on the brain, the spinal cord, and heart; they have consequently been recommended and employed as antidotes to each other in cases of poisoning" going on to make the extravagant claim that "this matter is now positively and satisfactorily settled; hence in all cases of poisoning by belladonna the great remedy is morphine, and its use may be guided by the degree of pupillary contraction it occasions."