In seeking normal standards on which to base vital capacity readings, practically all investigators have found a considerable percentage of unexplained low readings in persons supposed to be normal. That there is a decided variation in the lung capacity of normal persons cannot be questioned, though recent work has tended to reduce this variation by corrections for age, sex, weight, height, surface area, chest circumference, sitting height, etc. In going over the vital capacity records recently of 1,304 male university students selected at random, we1 pointed out that many of the low readings could be accounted for on the basis of past or present diseases. The present study was undertaken with a view to noting the effect of certain past intrathoracic diseases on the vital capacity. Few, if any, of the series reported heretofore have been correlated with as complete a history and physical examination as was available in the