Jean Civiale, 1792-1867, deserves credit for refining and popularizing the technique by introduction in 1826, of a markedly improved instrument composed of two sliding blades, introduced in the same manner as a sound, between which the stone is seized and crushed by the gradual pressure of a screw that is engaged and disengaged by the quarter turn of a disc; the fragments being washed out in the urine or by irrigation.