Dr. F. T. Graves lectures about a method of treating renal stones by partial nephrectomy and gives the scientific facts on which the operation is based. Firstly, Graves recounts his interest in this procedure; in 1952 having encountered two separate operations where the removal of a kidney stone has led to complications and the removal of the entire kidney (there are interesting establishing shots of a London street and views across the rooftops of London). Then, considering historical medical literature, he talks about the difficulty of this procedure versus the discomfort it produces (referring to Hippocrates, Pepys and Napoleon). Ultimately, understanding the architecture of the renal system and planning the operation is important in the success of the procedure. Graves uses models and medical illustrations to enliven his discourse.