Pathology is a variant of physiology with obstacles. No arterial wall is absolutely impermeable. The basic form of arteriosclerosis results from a disturbance of the lifelong flow of humors ab intima in adventitiam et ex centro in peripheriam (author's "Perfusion theory"). Special forms develop from this basic form. Analysis of postmortem material with special reference to the so-called risk factors allowed us to establish connections between some of these factors and arteriosclerosis, while some other connections, e.g. with smoking, were called in question. It is pointed out that prospective treatment of arteriosclerosis will begin only when the cluster of risk factors can be broken down.