The presence of various forms of fatty materials, i. e., lipoids, in the kidney in acute nephritis is one of the most important histologic findings. The relation of these substances to the altered functions of the kidney and to the latter stages of chronic nephritis is not well known. An understanding of these relations would serve as stepping stones toward the solution of many problems which are of vital clinical importance.
An experimental study of lipoid changes in nephritis in animals offers an approach which at present is not possible in dealing with early nephritis in man. It is only in exceptional instances that gross material can be obtained from a patient with early nephritis, since he either recovers or progresses on to a chronic condition.
In producing kidney changes we have used uranium nitrate because the histology of this type of experimental nephritis has received a great amount of