16 THE COMPOSITION OF EXPIRED AIR, 



e\[)ireil. Variations in the amount of organic matter contained in the inhaled air 

 may possibly iutlueuce the result, but this influence must be alight. Ransome's 

 results indicate that the age, health, and vigor of the pei'son may aflfect the amount 

 of organic matter exhaled, and Di-. Bergey's expeiiments with the fluid obtained 

 from the consumi)tive )>atient show that a smallei- i)ro[)ortiou of ammonia ami a 

 larger amount of oxidizable matter were pi'eseut in it than in the fluid collected 

 from a healthy man. It should be remembered, also, that it is extremely difficult 

 to oljtain accurate results in quantitative determinations of such very minute 

 amounts of ammonia and oxidizable matters as are found in expired air, and a part 

 of the differences in i-esults obtained is no doubt due to unnoted differences in 

 the details of the experiments. 



The results of tests for the presence of an organic alkaloid in the condensed 

 fluids obtained by Dr. Bergey were negative, corresponding to those leported by 

 Lehmann and Jessen (25) and by Ben (31). 



The results of attempts to condense the moisture of the aii- in the hospital ward 

 (Appendix, III., 3) were not satisfactory, and the determinations of ammonia in the 

 fluid obtained are not comparable, except that they show that the placing of a dust 

 filter in front of the condensing apparatus causes a marked reduction in the propor- 

 tion of ammonia in the condensed fluid. The evapoi-ation equalled the condensa- 

 tion except on days when the external air was saturated with moistui'e, hence no 

 moistuie was collected on clear days, bnt on such days some dust particles may 

 have accumulated in the apparatus which had no filter. 



Some expei'iments wei-e made to determine the amount of oxidizable matters 

 in atmos[)heric air, the results of wliich aie given in Table F, in the appendix. 

 These results differ greatly, some showing a mere ti'ace of organic matter, others 

 showing an amount which consumed .204, .3-40, and .558 giammes of oxj'gen per 

 1000 cbm. of air. The great differences in the amount of ammonia in air found by 

 diffei-ent obsei'vers as tabulated by Kenk (38, p. 40), and as reported by Remsen 

 (39), Miss Talbot (40), Nekam (41), Archarow (42), and Abbott (36), while 

 evidently in [wut due to differences in methods of experiment, must be more largely 

 due to differences in the amount of organic dusts in the air in different places or in 

 the same place at different times, than to differences in the amount of ammoniacal 

 gases or oi-ganic vapors in tlie air, and the same is true with regard to the differ- 

 ences in the amount of oxidizable organic matter in the air reported by Angus 

 Smith (12), Carnelly and Mackey (43), and others. 



Several series of experiments were made to determine the nature of the gaseous 

 mixtui'es in which small animals die witli .symptoms of asphyxia. The first of these 

 series were repetitious of the experiments reported by Hammond and described 



