Comparisons with 14 normal, younger, male native residents of La Paz showed that 20 patients with Monge’s syndrome have significantly higher mean body surface areas, hemoglobin, resting tidal volumes [VT (BTPS)], and resting minute volumes [VE (BTPS)]. If [VE (BTPS) is subdivided into its components of alveolar [Va (BTPS)] and dead space ventilations [VDS (BTPS)], it becomes apparent that the former is significantly smaller and the latter much larger in the Monge patients than in the controls. Alveolar hypoventilation in the Monge group is evidenced by an elevated mean PaCO2; a lower mean pH of 7.349, contrasted with that of 7.399 in the controls; a PaO2 of 48.1 mm Hg, compared with 57.7 mm Hg in the normals. Simultaneous surface scanning of the right upper and lower lung zones, using a central venous injection of 131I-HSA (human iodinated serum albumin), showed a reduction of total isotope activity in the right upper zones of the Monge grou