COMPOSITION OF URINARY CALCULI BY X‐RAY DIFFRACTION Collected Data from Various Localities Parts XII‐XIV Northern Ireland, South Africa and Kuwait

SUMMARY As part of a world survey of stone composition the crystalline constituents present in collections of upper urinary tract calculi from Northern Ireland, South Africa and Kuwait have been determined by the X‐ray powder method. The Northern Ireland stones contain more calcium phosphate than any comparable collection studied so far. Increased amounts of this compound have also been found in other areas of Great Britain and are only partly a result of the number of infection stones consisting of calcium phosphate and struvite. The major constituents of the South African collection are oxalate and phosphate as in most collections of upper urinary tract calculi, but the amount of uric acid (12 per cent) is greater than that found in any collection of such stones from countries outside Central Europe and Israel. The collection from Kuwait is similar to those from America, India and Turkey, all of which contain a very large amount of calcium oxalate. Some of the stones from Kuwait consist of a mixture of calcium oxalate and ammonium acid urate, a combination of compounds commonly found in endemic children's bladder stones from certain areas of technically‐developing countries but not usually encountered in upper urinary tract stones from industrialised areas.