Renal calculi have been studied and their cause sought by a host of interested workers during the past several years. The brilliant investigations of Dr. Randall and his co-workers1 have clearly pointed out the morbid processes in the formation of one type of renal stone. That there are other pathologic processes capable of producing renal calculi is plainly evident since the resulting bodies in the renal pelvis vary in composition and physical properties. The following 4 cases are submitted because the calculi were strikingly similar and appeared to present serial installments of identical pathologic processes. It is admitted that 4 cases are too few to justify dogmatic conclusions, yet only by the reporting of all cases of this kind will material be made available for further study.
REPORT OF CASES
—M. J. Z., a white man aged 43, had his first attack of pyelitis in 1934 and