Abstract
THERE is no detailed account of normal thyroid or adrenal growth over any considerable period of the life span of any vertebrate. The basic physiologic interactions involved in the thyroid-pituitary and the adrenalpituitary axes have been determined by experimental studies and although these investigations have established clearly the primary role of the pituitary tropic hormones in thyroid and adrenal function, there are certain problems of glandular inter-relationships which can be analyzed very profitably by a study of the growth of normal glands. The data on normal animals provide an important complement to experimental observations because it can be ascertained: 1. Whether sexual differences exist in gland sizes or growth rates. 2. If sexual differences are observed, these can be compared with the physiological changes which occur during the development of the reproductive system. 3. Whether the rate of growth of one gland is comparable with that of another.