mon to the diet of both birds and man or other environmental agents of possible etiologic significance might be identified. (The complete report from The People's Republic of China does, in fact, report on the analysis of food for nitrosamines and precursor compounds, and of food and drinking water for trace elements.) While that report deals with only one type of cancer, the multispecies approach might apply to some other types as well. Thus, chickens, particularly those of advanced age, might be excellent sentinels in agricultural environments for the occurrence of carcinogens that could affect other animals, man included.