There are few practitioners of medicine who neglect acute changes that occur in the kidneys as complications or sequelæ of such diseases as scarlet fever, diphtheria, pneumonia, and acute arthritis. As the pathologic processes in these acute diseases are fairly definite, albumin and casts are easily detected on routine examination. Failure to watch the urine in such cases is unusual because text-books call attention to its importance and insist on the necessity of comparative analyses in making a prognosis.
There is, however, another class of diseases in which complications referable to the kidneys are less common and consequently more often neglected. This oversight may be, in part, because we have not had our attention directed to nephritic changes in the diseases referred to in this paper with any insistence as to their significance; or it may be that while the kidneys are diseased in