Whole adrenals of the young adult hamster were maintained in culture. In most of the experiments the organ was supported on lens paper, but, latterly, cellulose and gelatin sponge were used. The culture media employed were (1) Ringer\u27s Solution (no nutrient), and (2) a nutrient mixture consisting of modified Krebs-Ringer\u27s Solution, lactalbumen hydrolysate, yeast extract and horse serum. The maintenance period was up to seven days, and the culture medium was freshened regularly in certain cases. Organs were weighed at the beginning and end, and sometimes during maintenance. Histological appearance at termination was compared with that of a freshly extirpated adrenal. In absence of nutrient, weight remained constant for the first day of culture, decreased over the following two to three days, and then leveled off at about 60 percent of its initial value. By contrast, organs cultured in the nutrient medium showed quite random variations in weight. There appeared to be no correlation between maintenance of weight and histological preservation; in point of fact, all organs which were well preserved after more than one to two days in vitro had lost weight considerably. Histological criteria are discussed
