In adrenalectomized dogs (cf and non-pregnant 9 ) the non-protein N of the blood showed a marked rise when characteristic symptoms, especially refusal of food, developed. The increase became constantly greater until death. An increase in urea N is the great factor in augmenting the non-protein N, but the "undetermined fraction" also increases, often greatly. There is no significant change in uric acid, sometimes a relatively small increase in creatinine and amino-acid N. Blood-sugar percentage is not materially altered until near death, when there may be moderate diminution. In a few instances in which the serum Ca was determined it seemed to be somewhat increased with onset of the symptoms. Blood Cl is often moderately diminished. The increase in non-protein and urea N often immediately precedes serious symptoms, coming on when the animal seems in good health. The undetermined fraction may also show some increase at this time. A concentration of the blood, with increase in solids, specific gravity, hemoglobin percentage, erythrocyte count, and relative volume of erythrocytes, can usually be detected somewhat in advance of the onset of symptoms. The change then increases till death, and is approximately coincident with that in the non-protein N. Possible relationships of the 2 sets of changes to each other and to the development of the clinical picture are discussed.