These studies are concerned with the origin of scar tissue in healing of the lung. They were undertaken chiefly because of the recent experiences of others who questioned the previous conception of the development and structure of the lung. All experiments were performed on dogs under sterile conditions. The positive pressure apparatus of Erlanger-Gessel was employed. The first group of experiments illustrate the effect of simple incision and suture of pulmonary parenchyma.
SIMPLE INCISION AND SUTURE OF PULMONARY PARENCHYMA
—A single incision, 2 inches (5.0 cm.) long, which ran at right angles to the axis of the main bronchus was made in the right lower lobe of a dog's lung on Dec. 31, 1928. This incision included several blood vessels and bronchi. The animal showed no discomfort and was killed on the tenth day, by means of an overdose of ether. The chest cavity was reopened under positive