Lymphatic Permeability to Albumin

Radioactive albumin was infused proximally into a leg lymphatic of dogs at a constant rate, thoracic duct lymph and blood were sampled for 150 minutes and the radioactive albumin in these fluids determined. The infused albumin returns to the circulation primarily by the thoracic duct. Less than 3% of the infused albumin reaches the circulation by routes other than the thoracic duct except in unusual cases of right and left thoracic duct anastomoses. Lymph nodes do not phagocytize the serum albumin passing through them and exchange of albumin between lymph and blood in lymph nodes is quantitatively insignificant.