NOKMAL PKOCESSES OF ENEKGY METABOLISM 545 



of absorbers. The first immediately following the rotary blower consists 

 of two Williams bottles containing sulphuric acid which wash out all of 

 the water from the expired air and water left over from the moistener 

 bottle. The other two are duplicate trains for absorption of carbon dioxid. 

 Each consists of two soda lime bottles and a Williams bottle containing 

 sulphuric acid. By thus reducing the size of each unit a smaller and much 

 less expensive balance can be employed for weighing the absorption of 



"Fig. 21. The Benedict Universal respiration apparatus as employed Toy the writer. 

 The spirometer and tubes leading to the face mask are carried on* a separate stand 

 so that they may be adjusted to a subject in the reclining, sitting or standing position. 

 Oxygen is supplied from a pressure cylinder and is measured on its way to the 

 spirometer by the meter. Two sets of absorbers are used so that observations may 

 be made continuously in successive periods. 



carbon dioxid. Oxygen is fed into the circuit from a high pressure tank 

 through a reduction valve and on its way is measured by a Bohr meter. 

 The spirometer and tubes leading to the subject are mounted on a separate 

 standard so that the height of the mouth-piece can be adjusted for a sub- 

 ject in the reclining, sitting or standing position. The same apparatus, 

 therefore, can be used for basal metabolism, for work experiments, or 

 for observations on the influence of food. 



The technique as worked out in the writer's laboratory for operation 

 of this instrument is briefly as follows. Let us suppose a basal metabolism 



