THE EFFECT OF CO₂ AND 0₂ CONTENT OF THE BLOOD ON THE FREEZING POINT OF THE PLASMA

¹ The Yale University School of Medicine, New Haven, Connecticut

1. The effect of CO₂ and 0₂ on the osmotic pressure of plasma has been estimated by measuring the freezing point depression of plasma whose blood had been equilibrated at 38° C. with gas mixtures of different composition.

2. At constant oxygenation, for each millimol of CO₂ added to one kg. of water of the blood, the osmotic pressure of plasma rises by 0·9 milliosmols per kg. of water.

3. If the CO₂ content of blood is kept constant, the reduction of one millimol of hæmoglobin (m. wt. 17,000) per kg. of water lowers the osmotic pressure of blood by about 0·3 milliosmol per kg. of water.

4. The biochemical implications of these findings are discussed.

Note:

We wish to thank Dr. D. I. Hitchcock for reading the paper and for his criticism.