Abstract

1. In a man with pulmonary emphysema, chronic bronchitis, and recurring cyanosis not associated with dyspnoea, the blood flow in the hands was increased by oxygen inhalation by an amount varying from 30 per cent to 70 per cent of the combined flow in the two hands in experiments made on different days during a period of two months.

2. In general, a greater percentage increase under oxygen inhalation was obtained when the initial flow was relatively small than when it was large. In this patient the normal flow (without oxygen inhalation) was habitually large, quite as large as in any of the normal cases studied and larger than the average of the normal cases.

3. The action of oxygen on the blood flow was not associated with any sensible change in the respiratory movements.

4. The action of oxygen on the blood flow was not associated with any certain change in the alveolar carbon dioxide tension.

5. It was therefore conditioned in some way by the increased alveolar oxygen tension. Possible ways in which this could affect the flow are discussed.

6. Oxygen inhalation produced no sensible change in the rate of the blood flow in the hands of two normal men.