(Young et al., 1960). Correlation between the degree of atheroma of coronary and carotid arteries is likewise high (Young et al., 1960;Mitchell and Schwartz, 1965). When necropsy evidence of myocardial infarction is made the starting point, the prevalence of carotid stenosis is again high, the lumen of the sinus being reduced by half in 59% of men with myocardial infarction against 35% in unselected necropsies (Mitchell and Schwartz, 1965). Conversely, when atheroma of the carotid sinus is the starting point the prevalence of myocardial infarction rises from 8% in cases with mild atheroma to 67% in severe cases (Martin et al., 1960).Embolisation from the heart to the carotid and cerebral circulation is also a common pathological finding. In a series of cases of occlusion of the internal carotid artery 20% were caused by emboli