Lung Tissue (IMAGE) Salk Institute Caption These microscopic images of lung tissue from newborn mice show a cross section of the alveoli, the buds in lungs where air exchange takes place. The air sacs (white) in the alveoli on the left, which were taken from a normal mouse, have expanded fully, indicating the animal could breath normally. Those on the right have failed to expand, because the mouse suffered from a new respiratory syndrome discovered by Salk scientists. Credit Courtesy of Salk Institute for Biological Studies Usage Restrictions News media reproduction to illustrate this story permitted with proper attribution as provided above. For one time use only. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.