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Adrenalectomized rats are known to have a defmitely increased salt need, inasmuch as the administration of large quantities of salt either greatly reduces or eliminates the symptoms of insufficiency, and actually increases the survival incidence (Rubin and Krick, 1933; Gaunt, Tobin and Gaunt, 1935; Kutz, McKeown and &lye, 1934). But is this need accompanied by an increased salt appetite, and will the adrenalectomized rat, if given free access to salt take sufficient quantity to keep itself alive and free from symptoms of insufficiency. 3 In an effort to answer these questions the following experiments were undertaken. METHODS.

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BALTIMORE, MARYLANDT HE RESULTS of previous self'selection experiments showed that removal of the adrenals in rats greatly increased the appetite for sodium chloride (i, i). In some instances the appetite as reflected in the voluntary salt intake increased 10 to 18 times over the preoperative level. Incidental observations indicated that adrenalectomy also lowered the taste threshold for salt. With a slightly modified self-selection technic a special study has now been made of salt taste thresholds of normal as well as of adrenalectomized rats. METHODSAt the outset each rat had access to i graduated inverted bottles filled with distilled water. After 8 to 16 days when the intake from each bottle had reached a fairly constant level, one bottle was filled with a sodium chloride solution of an estimated subliminal concentration. Each day there' after the concentration was increased in small steps until the rats manifested a consistent preference for the salt solution. The concentration of the salt solution at the point of divergence of the water and salt solution intake curves was taken as a measure of the taste threshold.In order to make certain that any distinction made by the rats between the salt solution and the distilled water depended entirely on the salt con' tent and not on any extraneous factor, the following precautions were observed: the two bottles were cleaned and refilled each day; the distilled water used for the salt solution and for the water bottles was always taken from the same source of supply; the fluids in both bottles were kept at the same temperature; the same two bottles were used throughout the experiment, one bottle for distilled water, the other for salt solution; and each bottle was kept in its original position in the cage.The rats had constant access to the standard McCollum diet which contains i per cent sodium chloride.In the experiments dealing with the taste threshold of adrenalectomized rats, the operation was performed when the intake from each of the two distilled water bottles had reached a fairly constant level. On the day following adrenalectomy one bottle was filled with the salt solution of estimated subliminal concentration.

IN previous self-selection experiments it was found that adrenalectomized rats showed a greatly increased appetite for sodium chloride and that when given access to salt separately from their food they took enough to keep themselves alive and free from symptoms of insufficiency (Richter, 1936). It was further found that after implantation of adrenal tissue or after treatment with 1-desoxycorticosterone acetate the adrenalectomized rats reduced their salt intake to normal amounts (Richter and Eckert, 1938). Thus by their appetites the untreated adrenalectomized rats indicated that they needed salt, while those in which the adrenal cortical insufficiency was corrected indicated that they did not need additional salt.We have now applied this method of appetite study to the investigation of the changes in sodium chloride and water needs produced by injections of desoxycorticosterone acetate in normal animals. We were interested to determine whether such rats would indicate by their appetite that they needed less or more sodium chloride. In view of several recent reports that normal animals treated with desoxycorticosterone acetate manifest a diabetes insipidus-like syndrome, we were also interested to determine whether, when given full opportunity to regulate their sodium chloride needs, such animals would still show an increased thirst (Ragan, et al, 1940;Harrop and Thorn, 1937;Thorn, et al, 1938; Clinton and Thorn, 1942; Mulinos, et al., 1941;Silvette and Britton, 1938;Kuhlmann, et al., 1939;Corey, et al, 1939). METHODSThe experiments to be reported were carried out in 3 series. In the first series 8 adult male rats were kept in individual cages and given free access to a 3 per cent solution of sodium chloride, a 1 per cent solution of potassium chloride, tap water, and our stock diet made without added salt and with unsalted butter. 2 Records were made daily of ^he food and fluid intake, and weekly of the body weight. Fluids were changed twice weekly. After 15 days

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