PAPERS OX MEDICINE AND PUBLIC HEALTH 



change. The first attempt is often unsatisfactory, but 

 the second or third attempt will invariably give reliable 

 results. The observations are made rapidly, and con- 

 sume from three to five minutes for each patient. 



VITAL CAPACITY OF NORMAL ADULTS 



The approximate normal vital capacity of an individual 

 must be known before readings are of much significance 

 in the diagnosis or prognosis of disease. The normal 

 vital capacity for men and women of average physical 

 fitness has been computed by Dreyer and others who 

 used the height, weight, chest measurements, stem length 

 or surface area as the basis for their calculations. The 

 normal vital capacity varies considerably with such fac- 

 as obesity, age. occuption and previous physical 

 training and experience. An athletic person or one who 

 plays a wind instrument or takes other strenuous exer- 

 cise will have a greater vital capacity than an inactive 

 person. All these factors must be taken into considera- 

 tion. A vital capacity below 15' . of the normal may be 

 looked upon as being of pathologic significance. 



The recent work tends to confirm the original obser- 

 vation made by Hutchinson of the relationship between 

 the vital capacity and height, and of its tremendous va- 

 riability, although it is more constant than compared with 

 weight. Lungsgard and Van Slyke contend that chests 

 measured according to certain formulas and found to 

 agree in size would more nearly have the same vital 

 capacity than would persons of the same height, a con- 

 tention which is denied by Peabody. Christie and Beams, 

 using the "linear formula" of DuBois. have demon- 

 strated that the surface area and not the height or weight 

 or chest measurements is by far the most constant anil 

 exact standard for comparison. This confirms the ob- 

 servations made by Dreyer and by West. From obser- 

 vations on 290 normal men and women, Christie and 

 Beams conclude that "a female from 20 to 30 year- 

 age, with a body surface of 1.4 to 1.5 square meters, has 

 a vital capacity of 2.700 c. c. and for each gain of 

 square meter in body surface the vital capacity g 

 up about 175 c. c. A male from 20 to 30 years of age, 

 with a body surface of from 1-6 to 1.7 square meters, has 



