Werner G. Jaffé
The interest in the nutritional impl1cations of selelnium came from the 1dentiricaticn of this element as the causative agent of the alka11 diseas in horses and somewhat later also o: the blind staggers disease of cattle. The toxicological aspects were therefore investigated much earlier than the role of selenium as an essential element (1). It was only after factor 3 was identified as a selenum-containing compound (2) that this element became of general interest for nutritionists. As is so often the case, the pendulum swung completely to the other side, and the toxicological aspects were clouded by the possible nutritional implications, which nevertheless still remain obscure.