PAPERS ON MEDICINE AND PUBLIC HEALTH 423 



In thirty suspected cases in which the roentgenograms 

 showed no evidence of disease, the mean vital capacity 

 was 102 per cent of the normal, the range being 82 per 

 cent to 122 per cent of the normal. 



In thirty-nine cases showing unilateral peribronchial 

 tuberculosis, the average vital capacity was 97% and the 

 range from 81 to 121 r i of the normal. 



Seventy-one cases of unilateral and seventy with bi- 

 lateral parenchymatous tuberculosis revealed by the 

 stereo roentgenograms were grouped according to the 

 extent of involvement. The vital capacity of the groups 

 was found to decrease as the extent of the disease in- 

 creased, the average being 7V< , and the range from 26 

 to 122% of the normal. 



On the basis of physical examination, in ninety cases 

 showing no evidence of tuberculosis or in which a defi- 

 nite diagnosis was not made, 90% gave vital capacities 

 within normal limits, while variations of 70T to 90% oc- 

 curred in the remaining 10%. 



In 172 cases showing varying degrees of pulmonary 

 disease, the vital capacity was found to be decreased in 

 proportion to the extent of involvement. The vital ca- 

 pacities of 30 cases, showing pulmonary cavities by the 

 roentgen-ray, ranged from 31 to 109% of the normal, 

 the average being 64' < . Nine cases of spontaneous pneu- 

 mothorax showed vital capacities averaging 49^, the 

 range being 32% to 58^ of the normal. 



III. Bronchial Asthma. 



Peabody, Wentworth and Barker, and others have re- 

 ported vital capacity readings in patients suffering from 

 bronchial asthma, and found that in some cases the lung 

 volume was considerably decreased, and in others, it was 

 normal. 



Meyers, reporting 20 cases in which the readings were 

 taken at various times during and between the attacks, 

 found the vital capacity was reduced tremendously dur- 

 ing the attacks, in some cases to 20% of the normal, which 

 quickly returned to the normal as the attack disappeared. 

 In four cases in which the disease had extended over a 

 period of years, the vital capacity did not return to nor- 



