This paper is a contribution to the natural history of error. In these days of enthusiastic renal surgery every frank analysis of diagnosis gone wrong, of operative blunders committed, of difficulties unexpectedly faced, must be not only of interest but of actual value to those undertaking operations on the kidney. It is a trite enough observation that we learn more from defeat than from victory—this is my apology for directing attention to certain of the errors observed during the development of the cases recorded in this article.
Jacobson describes nephrolithotomy as "one of those advances in modern surgery in which the operation has outstripped the diagnosis."1 This statement is borne out by the astonishing fact that of twenty-seven nephrotomies for stone he met failure in six. Henry Morris also remarks that within his observation sixteen unsuccessful explorations of the kidney had occurred. Those who are overconfident of their own