Differences of opinion are still encountered as to the mechanical effect of induced paralysis of the hemidiaphragm on the volume and function of the corresponding lung. Yates1 expressed the opinion that the motion of the parietes of the chest can be limited by blocking the nerve trunks which transmit motor impulses to the diaphragm. He stated that surgical paralysis and consequent atony of the diaphragm induce a reduction in the movements of the thoracic parietes of the chest or, even if there are adhesions, a reduction in the volume of the lung, and the pulmonary excursions are limited to those immediately above and below the mean inflation. Lilienthal2 said that clinical results and roentgenologic appearances led him to the conclusion that the elevation of the diaphragm after having crushed the phrenic nerve may effect a reduction in capacity the equivalent of from 200 to 500 cc. and also