Water diuresis in the domestic fowl.

1. The exteriorization of ureters in domestic fowls allows the collection of urine uncontaminated by faeces.2. When water is administered by stomach tube to a fowl, water is stored in the crop, from which it is slowly released into the proventriculus.3. Immediately after water gavage, there is a sharp rise of urine flow accompanied by an increase in endogenous creatinine excretion and a fall in the osmolarity of the urine. This initial increase in urine flow is of short duration, and is followed by a normal curve of diuresis with a peak at about 90 min after hydration.4. The first rise in urine flow following the filling of the crop appears to be of reflex origin, as distension of the crop with paraffin produces an enhanced excretion of urine and of creatinine.5. Changes in urine flow and in creatinine excretion are closely correlated.6. After water deprivation for 18 hr, the urine is slightly hyptertonic to blood. The maximum urine concentration observed was of the order of 600 m-osmole/l.