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The CO diffusion constant (Krogh's diffusion constant) has been estimated from the CO flux across layers with defined thickness under steady state conditions. At 22°C and in hemoglobin solutions with a concentration of 33 g% the diffusion constant for CO was found to be 3.3×10 cm min atm. This value is about 40% of the diffusion constant for CO in water. The relationship between the diffusion constant and the hemoglobin concentration was approximately linear in a concentration range of 10-40 g%. The temperature coefficient of the diffusion constant was −0.5%/°C both in water and hemoglobin solutions. At 38°C and in a hemoglobin solution with a concentration of 33 g%, the diffusion constant for CO was therefore 3.0×10 cm min atm, the diffusion coefficient 11×10 cm s. A general theory for the diffusion of CO in hemoglobin solutions has been derived. According to this theory the diminution of the CO diffusion in hemoglobin solutions in comparison to water can be explained quantitatively by a reduction of the water space by the hemoglobin molecules. The diffusion constant for CO in layers of erythrocytes was insignificantly (0-3%) smaller than in hemoglobin solutions with the same hemoglobin concentration. It is concluded that the erythrocyte membrane does not offer a considerable resistance for the CO diffusion. [ABSTRACT FROM AUTHOR]

Focuses on the development of gastroenterology during fifty years. Change of the technic of gastrectomy since its conception in 1881; Creation of tubes, string tests and artificial distention of the stomach with carbon dioxide; Rapid evolution of gastroenterology from medical and surgical standpoints.