Abstract
Material giving a very strong periodic acid-Schiff reaction was seen in mouse pituitaries and proved to be glycogen. In mice 8 days and younger, glycogen could be demonstrated in the intercellular spaces and in the cells of the neural lobe, in the cells of the pars tuliberal is, and intercellularly in the stalk and median eminence of the hypothalamus. At 5 days and less, glycogen also appeared to be located in irregular patterns in the sinusoids of the anterior lobe. After 8 days of age, glycogen was apparently restricted, in the pituitary system, to the pars tuberalis. After one month the amount of glycogen was considerably reduced, but nevertheless could still be demonstrated at 7 months.