Some quantitative aspects of the circulation in goats have been studied to furnish basic information for other experimental work. The I131 method for plasma volumes and the Cr51 method for red cell volumes were tested and found useful. By this means, the balances of plasma volumes, red cell volumes, plasma proteins, and lood hemoglobins have been measured before and after severe hemorrhage. The F cells and F hemoglobin values are discussed in relation to Cr51 cell volumes and cell volumes calculated from the I131 plasma volumes and hematocrits. Plasma volumes per kilogram of body weight are compared with volumes obtained by others.