l8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 63 



and Ercklentz in Flugge's laboratory' which seem to show that, 

 in people both well and sick, chemical changes in the character of the 

 air in inhabited rooms exercise no deleterious effect on the health of 

 the dwellers Dr. Sewall reviews Leonard Hill's work which shows 

 that the motion of the air in the experimental chamber by means 

 of electric fans almost entirely annulled the sense of discomfort.' 

 He then cites the astonishing experiments of F. G. Benedict and 

 R. D. Milner' who kept a subject for twenty-four hours in a cham- 

 ber, the air of which held an average carbon dioxide content of 220 

 parts per 10,000 or over seventy times the normal, together with a re- 

 duction of oxygen to less than 19 per cent. The humidity was kept 

 down and the temperature held uniform. The subject of the experi- 

 ment suffered no discomfort. 



Boycott and Haldane, referred to above, express the opinion that 

 " the alveolar carbon dioxide tends to a lower level in warm 

 weather " and that this diminution in the alveolar carbon dioxide 

 is associated with a feeling of warmth of a rather unpleasant kind 

 rather than with any absolute point on the thermometer ; they hold 

 that the rise in the carbon dioxide tension is associated with the 

 general exhilaration and stimulation produced by cold air. 



And now comes Leonard Hill, the physiologist, of London, who 

 with his staff at the London Hospital conducted several noteworthy 

 experiments which he described before the Institution of Heating 

 and Ventilating Engineers in March, 191 1.' In view of the fact that 



ration (Journal of Physiology, 1908, Vol. 37, p. 359). See also Preventive 

 Medicine and Hygiene, by Milton J. Rosenau, M. D., Chapter 4, D. Appleton 

 & Co., 1913. Prof. Rosenau's work contains the latest word on the bacteria 

 and poisonous gases in the air, ventilation, etc. 



Thomas R. Crowder, M. D. : A Study of the Ventilation of Sleeping Cars 

 (Archives of Internal Medicine, January, 191 1, and January, 1913). This 

 elaborate investigation is illustrated by numerous diagrams showing the 

 carbon dioxide content in the air from the aisles, the upper and lower 

 berths and smoking rooms. 



' Zeitschrift f. Hygien. u. Infectionskr., 1905, Vol. 59. 



^Leonard Hill: The Relative Influence of Heat and Chemical Impurity 

 of Close Air (Journal of Physiology, 1910, Vol. 41, p. 3). 



See also Leonard Hill, Martin Flack, James Mcintosh, R. A. Rowlands. 

 H. B. Walker: The Influence of the Atmosphere on our Plealth and Com- 

 fort in Confined and Crowded Places, Smithsonian Miscellaneous Collections, 

 Vol. 60, No. 23, p. 96 (Publication 2170), 1913. 



' Experiments on the Metabolism of Matter and Energy in the Human 

 Body, Bulletin 175, U. S. Dep. Agriculture Ofifice Experiment Station, 1907. 



*Journ. Amer. Med. Ass., April 8, 1911. 



