The oxygen and carbon dioxide content of the blood of normal and pregnant decerebrate cats

The micro-manometric method of Van Slyke & Neill [1924] for the combined determination of oxygen and carbon dioxide in blood was used. The procedure was that for 0-2 c.c. samples in the 50 c.c. apparatus. Small samples were analysed because this study was carried on in conjunction with foetal blood studies in which larger quantities were rarely obtainable, and comparable sets of values were desired. The blood was withdrawn under heavy mineral oil into tuberculin syringes through no. 27 needles containing minute amounts of heparin and was usually analysed within an hour. The blood was introduced below the gas-freeing solution in the pipette of the manometric apparatus directly from the needle of the syringe. Most samples were taken from the femoral vessels, after dissection, but some were taken from the saphenous vein without dissection. The arterial and venous samples were not obtained simultaneously, from less than one to several minutes elapsing between their withdrawal. Normal cats were strapped in resting position in a canvas hammock and local procaine infiltration of the femoral region was commonly 1 Aided by grants from the American Academy of Arts and Sciences.