1. A readily reproducible pathological lesion closely resembling that typical of the "transfusion kidney" has been obtained by the injection of hemoglobin into rabbits having acid urine, whose renal tubules had previously been damaged to a moderate degree by (a) a short period of complete renal ischemia, or (b) the administration of a specific chemical poison—sodium tartrate.
2. It has been found that hemoglobin is precipitated in the tubules of damaged kidneys excreting either acid or alkaline urine, in contrast to the absence of hemoglobin precipitation in normal kidneys.
3. In the acid state hemoglobin casts are more numerous and more persistent than in the alkaline, and are associated with renal functional disturbances, in contrast to the lack of such disturbances when the urine is alkaline.
4. The ultimate outcome, both anatomically and functionally, in any given instance is determined by variations in the degree of tubular damage, the level of hemoglobinemia, and the urinary pH.