424 ILLINOIS STATE ACADEMY OF SCIENCE 



mal limits after the disappearance of the asthmatic at- 

 tacks. In these cases, physical and roentgen-ray exami- 

 nations revealed definite evidence of emphysema, which 

 apparently was sufficient to account for the reduced hmg 

 capacity, 



IV. Pneumonia. 



In pneumonia, Meyers found the vital capacity to be 

 very low from the beginning, being reduced to 50% or 

 less in most cases. This marked reduction from the be- 

 ginning of a case of pneumonia, he points out, is almost 

 diagnostic. The lowest vital capacity was observed on 

 or near the day of crisis. From this time on, if the pa- 

 tient recovers, the vital capacity gradually increases 

 through convalescence. An increase in the vital ca- 

 pacity is noted almost immediately after the crisis, but 

 does not return to normal for many days. The amount 

 of pulmonary consolidation bears no relationship to the 

 vital capacity, as is true also of the relationship between 

 consolidation and dyspnea, as pointed out by Means and 

 Barach. They also point out that the dyspnea may in- 

 crease after the crisis, with no evidence of alteration in 

 the anatomic processes in the lungs. This, however, does 

 not hold true for the vital capacity, as an increase is 

 noted almost immediately following the crisis. The test, 

 therefore, is a valuable aid in the early diagnosis of pneu- 

 monia. In a case of unresolved pneumonia, the vital 

 capacity remained almost stationary for a period of ten 

 days following the crisis. In another case, in which the 

 tubercle bacilli appeared in the sputum, the vital capacity 

 remained stationary over a long period of time. 



Peabody and Wentworth suggested that the reduced 

 vital capacity present in patients convalescing from pneu- 

 monia may occur in any severe acute infection. Peabody 

 and Sturgis studied the effect of fatigue and general 

 weakness on the vital capacity, using patients suffering 

 from pernicious anemia. In none of these cases, without 

 a lung or heart disease, was the vital capacity reduced 

 more than 26% below normal. In another series of cases, 

 attempts were made to fatigue the muscles of respira- 

 tion by taking the vital capacity every fifteen seconds 

 for ten minutes. Contrary to what might be expected, 



