AND ITS EFFECTS UPON ANIMAL LIFE. 1 5 



The average for five specimens of liuid condensed from the expired air of a 

 healthy man four lioui's after he iiad taken a meal was 1 1.98, while the average for 

 six specimens from the breath of the same man half an hour after tin; meal was 

 only 8.S(i. For two specimens from the same man collected three and a half and 

 four hours after a meal, but just after the mouth had been thoroughly rinsed with 

 warm water, the average was 2.49. These I'esults indicate that the ammonia and 

 oxidizable organic matter in the condensed fluid were, to a large extent, due to 

 products of decomposition of organic matters in the mouth. The well known fact 

 that the amount of oxygen absorbed and of carl)onic acid given off varies accord- 

 ing to whether the person is fasting or has recently taken a meal, may possibly 

 be in [)art due to the same cause, l)ut the results obtained by Birkholz (37) indi- 

 cate that it can only be in part. Ransoine (11) reports no marked difference in 

 the amount of ammonia, or of oxidizable organic matter, as determined by the per- 

 manganate test, contained in the fluids collected from the exhaled breath soon after 

 a meal and in that collected from a fasting person. Beu (31) found a much higher 

 proportion of oxidizable matter in the fluid condensed from his own breath (50 

 mg. of oxygen required per litre of fluid) than was found in Dr. Bei'gey's experi- 

 ments. His results indicated the exhalation of 15 mg. of organic nuitter in 24 

 hours, the corresponding figure from Ransome's results being 20 mg. About 12 

 c. c. of fluid w^as collected from about 335 litres of air expired per houi-, being 

 nearly equal to the results obtained by Beu (31), who condensed 100 c. c. of the 

 fluid from three cubic metises of air expired in eight hours. 



Renk (38, p. 162) gives a table showing that in an average quantity of 9000 

 litres of air expired in a day by a healthy man, the amount of moisture may be 

 from 200 to 400 grammes, depending on the temperature and relative moisture of 

 the inspired air. With air containing 50 per cent, of moisture inspired at 25 ° C, 

 the amount of moisture is 293 grammes, or about the result given by Beu, referred 

 to above. 



Lehmann and lessen (25) found that between 3 and 4 mg. of oxygen were 

 required to one liti'e of fluid to effect oxidation, and note that more ammonia was 

 present in the fluid collected from a person with decayed teeth than in that ob- 

 tained from a person whose teeth were sound. The very considerable differences 

 in the amounts of ammonia and of oxidizable matter found in the fluids condensed 

 from expired air by diffei'ent expeiimenters, and by the same experimenter in 

 fluids obtained from the same person at different times, are probably due to sev- 

 eral different causes and their combinations. The amount of fluid condensed per 

 litre of expired air varies from .003 to .004 c. c. The soundness and cleanliness 

 of the mouth and teeth influence the amount of ammonia and oxidizable matter 



