Renal disease is quite common among wild animals albeit there are certain orders in which the lesions are less conspicuous. Clinical diagnoses of nephritis, and this is the only diagnosis attempted, have been made on monkeys by examination of urine which shows the same characters as in the human disease. In ungulates more attention is to be placed upon the cellular contents of the urine since renal epithelium is apparently shed more readily and casts less often formed. Signs and symptoms of renal disease are limited to edema and uremia; cases of the latter are rare enough to discuss separately at the proper place. ABSENCE OF ABNORMALITIES. Abnormalities of size, shape and position of the kidney are frequently reported in literature of veterinary medicine and aplasia has been described. Our material has failed to present cases of horse-shoe kidney well known to occur in horses, cows, sheep and dogs. Wandering kidneys are also known but have not been seen in our wild animals. Shall these abnormalities be considered as due to degenerative changes in cross bred animals or as the result of the strain of domestication? To such a speculative question our material affords no answer. HYPERTROPHY. That the kidney has the power of hypertrophy in a compensatory manner is illustrated by two cases. A Japanese Macaque (_Macacus fuscatus_) ♂ apparently had suffered with a unilateral nephritis which had gone into a contracted stage. At all events much functionating tissue was gone, the organ irregular and small, being half or less of the size of the other organ which was larger than is considered normal for the species. Histologically the large organ was practically normal. A common opossum (_Didelphys virginiana_) suffered with a complete suppurative nephritis of the right side which completely destroyed the organ; the origin of this is not clear as no ascending disease could be determined and no certain acute infection had existed; decomposition precluded satisfactory bacteriology. The left kidney was nearly twice its normal size and involved in an early diffuse nephritis, with miliary abscesses, in which the glomeruli did not participate. There were in these sections evidences of regeneration, swollen reduplicated epithelial coverings presenting a picture similar to those seen in so-called chronic nephritis secondary to interstitial change. INFILTRATIONS.