Composition and structure of renal and ureteral calculi in patients under covalitin therapy.

We examined the composition and texture of 53 urinary calculi from patients receiving Covalitin therapy. The texture of the infection stones and of concrements containing mainly apatite showed no changes as compared to concrements from control groups receiving no such therapy. Calcium oxalate stones more often showed a whewellite texture (Type 2) and a less frequent occurrence of weddellite (Type 4) as compared to the control groups. Surface or marginal changes indicating a possible litholysis could not be shown.