The lung, tracheal fluid, and lipid metabolism of the fetus.

Amniotic Fluid/analysis Animals Blood Pressure Body Fluids/metabolism Carbon Isotopes Chromatography Chromatography, Gel Chromatography, Thin Layer Female Fetus/metabolism Heart Rate Lipid Metabolism Lung/metabolism Pregnancy Proteins/analysis Sheep Surface Tension Surface-Active Agents/biosynthesis Trachea

Carbon Isotopes Proteins Surface-Active Agents