This is a monograph which records the results of experimental observations concerning the effect of both anoxia and asphyxia on the vasomotor mechanism. The authors sharply distinguish between these two conditions, and according to the results of their studies such distinction must be made between the mere absence of oxygen and the absence of oxygen combined with the presence of carbon dioxide. The methods of study are carefully given and the results evaluated. The modes of action of the vasomotor system are considered and explained. Carotid sinus reflexes and the respiratory and circulatory adjustment to the experimental conditions are discussed in detail. The bibliography is extensive and complete.