Composition of the Blood Gases During the Respiration of Oxygen.

The effect of breathing oxygen-rich gas mixtures on men and animals has been frequently investigated. The papers which we have consulted deal exclusively with methods in which the respiratory exchange was studied, and the general results of the more recent experiments confirm the view that there is little or no difference in metabolism, as indicated by the gaseous exchange, whether ordinary air or gas mixtures rich in oxygen are respired. A contrary opinion has been formed by some observers, such as Rosenthal ahd Lukjanow. We have been unable to find any paper later than the work of P. Bert which deals with the composition of the blood gases during oxygen inhalation. While engaged on a study of the nitrogen-content of the blood we accumulated a mass of data on the comparative quantities of carbon dioxide and oxygen in the blood of cats breathing air and high per­centages of oxygen. These results we bring forward in this paper. The cats were anæsthetised with urethane. The process for obtaining the samples of blood, the precautions to be taken in the evacuation of the gases by the tapless form of blood pump, were those described at length in a former paper, in which the mode of administration of oxygen has also been fully described. Respiratory tracings were taken in every case, but we do not consider it necessary to reproduce these.