The question whether the phosphate participates actively in the calculogenesis or whether it is only an accidental enclosure in the stone material can, in our opinion, only be answered by the quantitative determination of phosphorus in the stone material resp. in the organic stone matrix. The high enrichment of phosphorus in the stone material, in comparison with the urine, as well as its additional significant enrichment in the stone matrix, compared with the (crystalline) stone material, both deduced from our analytical data, nearly exclude a passive role of the phosphate in the calculogenesis. On the basis of our investigation we suppose that the phosphate crystalluriae, occurring spontaneously or induced, at moderate pH-values of urine, especially by Ca-oxalate, sometimes by urate crystalluriae, contribute to the crystal "density" in the urine, the sufficient crystal "density" being one of the preconditions for the formation of compact crystal aggregates; the other precondition is the presence of the reactive organic cement substance in a sufficient concentration. This active crystal agglomerating component is represented, in our conception, by partially hemolysed blood cells resp. by the cholesterol of their damaged membranes.