MUELLER VALVES AND BENEDICT APPARATUS. 



199 



is abnormal. This was probably due to over- ventilation, for if a calcu- 

 lation is made of the ventilation of the lungs other than that required 

 to sweep out the normal dead space, it will be seen that there would be 

 a greater volume of ventilation per unit of carbon dioxide in this period 

 than in the other two periods with the spirometer unit. The 190 c.c. 

 obtained in the experiment on March 29 for the carbon-dioxide elimi- 

 nation in the first period with the Mueller valves is also apparently 



TABLE 36. Variations of average results obtained with the Mueller valves and Tissot spirometer 

 from those obtained with the spirometer unit. 



4 5 6 7 6 9 IO 



PER CENT OF VARIATION 



FIG. 54. Probability curves for the series of comparison experiments with the spirometer unit 



and the Mueller valves. 



The ordinates indicate the percentage of the total number of periods and the abscissae indicate 

 the percentage of variation from the average. 



