Description: This film begins with Czermak's observations in 1866 and passes on to the effects on blood pressure of clamping the carotid arteries with and without section of the depressor or aortic nerves. The anatomy and histology of the carotid sinus is then demonstrated on the living animal and by diagram. This is followed by a similar series of demonstrations showing the anatomy of the aortic arch, the carotid sinus nerve and its embriological development, the aortic nerve and the histology of the carotid sinus nerve. The film has three sections Stimulation of the Aortic Nerve, Stimulation of the Carotid Sinus Nerve and Perfusion of the Isolated Carotid Sinus Preparation. ICI.