[Study of the distribution of kidney calculi in Vrastsa District].

The authors have studied the RCD spread in Vratza district according to the material of the therapeutic departments in the district for the period 1969--1973 and according to the material of the out-patient department -- polyclinical--1971--1973. During that period 16,294 patients with diseases of the urinary system were registered, 6311 out of them with RCD, i. e.