THE CONTROL OF THE RENAL EXCRETION OF WATER : I. THE EFFECT OF VARIATIONS IN THE STATE OF HYDRATION ON WATER EXCRETION IN DOGS WITH DIABETES INSIPIDUS.

Water and electrolyte excretion has been studied in a series of dogs with diabetes insipidus, in which the extent of neurological damage was subsequently determined. The animals were studied before and after the introduction of variables which produce marked changes in the state of hydration,-administration and restriction of water and the substitution of 0.5 per cent sodium chloride for it as a drinking fluid. Observations were made on those factors, both general and renal, which appear to be important in determining the excretion of water and electrolyte, or which may be expected to yield information on the mechanisms by which the regulation of such excretion is achieved. These are the volume of extracellular fluid and plasma and the concentration of the contained electrolyte, glomerular filtration rate, and the excretion of electrolyte, urea, and water itself, as well as the tonicity of the urine.