Abstract
Quinuronium sulphate liberated appreciable quantities of histamine from tissues of mice, rats and sheep. The signs of quinuronium poisoning in mice and rats were more severe than for compound 48/80. The animals acquired tolerance to the latter drug. Thus the toxicity of quinuronium probably depended on factors other than histamine release. Amicarbalide released amounts of histamine comparable with those liberated by quinuronium only in rat tissues.