A New Index of the Intrapulmonary Mixture of Inspired Air

In numerous studies it has been shown that the emphysematous lung is unevenly ventilated, the inspired air being more effectively mixed into some parts than into others, and it has been usual to express the results of such studies graphically. Some workers have emphasized the importance of the shape of the graph (Briscoe, Beck- lake, and Rose, 1951), whereas others have expressed the efficiency of intra- pulmonary mixing as indices related to one or other of the variables upon which the shape of the graph depends