There are many problems regarding the vascular system of the lung，especially on
the distribution of vasomotor nerves and capi11ary lymphatic vessels. The result of our experiments on this area wi1l be presented. Vasomotor Nerves to the Lungs
Dixon claimed that the sympathetic nerves do not exist in view of the finding
that adrenalin does not act on the pulmonary blood vessels. Barcroft et al. have reported that the blood flow rate is 4 liters per minute at rest，but it increases to 25 liters or 30 liters per minute in activity. The question ariscs whether such changes would occur without the control of vasomotor nerves. Majima (1921) has stated that vasoconstrictor nerves exist in the sympathetic nervous system in the toad， while Luckhardt anJ Carlson (1921) have reported that they exist in the vagus nerves in the tortoise. Experiments made on the material isolated from terminus of the vasomotor nerves have shown that the cholinergic nerves exist in the vagus nerves and the adrenergic nerves exist in the sympathetic nervous system in toads and tortoises. This has not yet confirmed on human beings and mammals. Lymphatic Vessels of the Lungs Cunnigham (1916)，Miller (1937)，etc. have stated that the lymphatic vessels are not distributed beyond the alveolar duct. After right lymphatic duct of the dog was ligated and the flow of lymph was suspended，vermilion-gelatin-Ringer solution was injected into the lymphatic vessels by 1/4 syringe under 30 mm to 40 mm H20 of pressure，and the pecimen was obtained. This specimen demonstrated that lymphatic vessels further extended from the alveolar passage to the periphery，that is the alveolus，alveolar sac and alveolar septum.