THE ANOXEMIA of pulmonary diseases differs from that found in persons at high altitude, mainly because arterial carbon dioxide tension and hydrogen ion concentration increase in the former and decrease in the latter. To estimate the importance of carbon dioxide and/or hydrogen ion in circulatory and respiratory adjustment, results in patients with Ayerza's disease were compared with those secured in patients with anoxic conditions without carbon dioxide retention, i.e., in patients at high altitude and in those with congenital heart disease.
At present some of the mechanisms of respiratory and circulatory regulation are not completely clear. It was thought that the comparative study of these functions in various types of anoxia could throw light on the subject. For that reason it was decided to investigate the circulatory and respiratory function in three different types of anoxia: (a) anoxic anoxia due to impairment of the pulmonary function, with low arterial oxygen