In this monograph, Ricker, who is well known for his excellent experiments on the innervation of the blood vessels, discusses in detail his conception of arteriosclerosis and hypertension. Most intensive nervous stimulation cases paresis of the constrictors of the media and stasis in the vessels of the adventitia. Compressed by the blood pressure inside of the vessels, the media is deprived of the nourishing tissue fluids and becomes necrotic. This is followed by sequestration and calcification. Less intensive stimulation leads first to an accumulation of the tissue fluids in the intima, loosening of the intima and hyperplasia of the connective tissue. Weak stimulation, finally results in constriction, narrowing of the lumen and hyperplasia of the media. One condition to which Ricker attributes much importance is the so-called peristasis. Stimulation of medium intensity produces an identical reaction of arteries and capillaries. Stimulation of the dilators leads to fluxion and hyperemia, that