BENEDICT APPARATUS, INCREASED DEAD SPACE. 217 



TABLE 39. Respiratory exchange in comparison experiments to study the effect of additional 

 dead space. Benedict respiration apparatus, (spirometer unit) . (Without food) .Con. 



The variations of the individual comparisons are given in table 40, 

 using the normal values as a base-line. With a dead space of 45 c.c. 

 the greatest variation in the respiratory exchange is shown in the ex- 

 periment with W. F. O'H., in which the carbon-dioxide elimination was 

 22 c.c. higher with the additional dead space than with the apparatus 

 as normally used. An inspection of the statistics for the individual 

 periods shows, however, that this difference was due to the fact that in 

 the periods normally carried out the subject was somewhat drowsy 

 and there was considerable apncea. With J. W. P. the respiratory- 

 exchange with the additional dead space was also slightly higher; 

 but this was likewise due more to variations in the degree of muscular 

 repose than to actual differences between the two methods. With the 

 other two subjects the difference in the respiratory exchange with the 

 two methods of breathing was insignificant. The four comparisons 

 with 90 c.c. additional dead space show an even better agreement than 

 with the 45 c.c. dead space, there being practically no difference in any 

 of the factors measured except those for the ventilation of the lungs and 

 the volume per respiration. With an additional dead space of 135 c.c. 

 there is also a good agreement between the values for the respiratory 

 exchange compared. With an additional dead space of 224 c.c. the 

 carbon-dioxide output is slightly higher with the increased dead space 

 than with the normal method, but this difference is not very great. 



