Abstract
A histologic study of the adrenal cortex in frogs, mice, rats, guinea pigs, rabbits, cats, dogs, monkeys and humans indicated that certain morphological appearances were associated with changes in functional activity, regardless of species. A tentative scheme of identification was developed and used on adrenal glands from animals subjected to a wide variety of experimental conditions. The relative proportion of the multiplying, accumulating, storage and secreting cell types in the adrenal cortex was found to be an important criterion of the demands to which it had been subjected. Eight typical states are described and illustrated with photographs and a schematic diagram.