The relation of selenium to western duck sickness

In 1936 Twomey and Twomey reported that 20-50 parts per million of selenium as sodium selenite in the drinking water produced poisoning in ducks in which the syndrome was identical with that produced by Clostridium botulinum type C, which had been considered the principal causative agent in western duck sickness (Kalmbach and Gunderson, 1934). In a more recent paper, Twomey, Twomey and Williams (1939) reported the analyses of a number of duck livers collected at various points near Great Salt Lake where the sickness is prevalent. These analyses show the presence of 7-148 p. p. m. of selenium, based on the oven-dried weight of the livers. In contrast, no selenium was found in duck livers obtained in Pennsylvania, where sickness has not been reported. As a result of these findings, a thorough investigation of the significance of selenium in outbreaks of western duck sickness was undertaken in the summer of 1940.