CRITICAL DISCUSSION OF RESPIRATION APPARATUS. 247 



the results did not agree with the calculated composition. Two more 

 alcohol check tests were made and again the results were very unsatis- 

 factory. The air in the spirometer was then forced out into a large 

 Douglas bag, thoroughly mixed, and returned to the spirometer. The 

 results of the subsequent analysis are given in the table as experiment 4. 

 Two additional tests were made in which the air was analyzed before 

 and after mixing in a Douglas bag. The results are given in table 44 

 as experiments 5 and 6. To find if the same conditions obtained during 



TABLE 44. Results of alcohol check tests with the Tissot apparatus. 



'Spirometer air mixed in a Douglas l>:i. 



respiration experiments with man, expired air was collected in the 

 spirometer and analyzed before and after mixing. The results are 

 given in table 45. In the first experiment the respiration was irregular; 

 the ventilation per minute was as follows: 5, 5, 17, 3, 3, 2, 7, 4, and 

 4 liters. Two samples were taken, the first at 9 h 30 m a. m. and the 

 second at 3 h 15 m p. m. Another experiment was carried out in which 

 the respiration was quiet and regular, the ventilation per minute being 

 10, 5, 10, 7, 6.5, 7, 6.5, 7, and 6.5 liters. Similar experiments were 



TABLE 45. Effect upon the analyses of mixing spirometer air. 



'Sample taken at 9 h 30"" a. m. 'Sample taken at 3 h 15 m p. m. 



