Ajeil 30, 1915] 



SCIENCE 



631 



entirely aside from its temperature. As 

 noted above, all the ordinary physiological 

 and psychological tests failed to show any 

 such effect ; but in one particular we noted 

 a difference in the behavior of the subjects 

 exposed to stagnant and fresh air of the 

 same temperature and humidity. In two 

 of our series of experiments standard 

 luncheons were served to the subjects in the 

 experimental chamber and the amount on 

 their plates was weighed. In one series 

 the subjects consumed on the stagnant days 

 an average of 1,151 calories and on the 

 fresh-air days an average of 1,308 calories, 

 an increase of 13 per cent. In a second 

 series during colder weather, the average 

 consumption was larger, 1,492 calories for 

 the stagnant and 1,620 calories for the 

 fresh-air days, an excess again for the 

 fresh-air days, this time of about 9 per 

 cent. The opinions of the subjects as to 

 their comfort slightly favored the stagnant 

 days, but it seems possible that odors of 

 some sort, not consciously perceived by 

 those exposed to them for several hours, 

 may yet affect the appetite and hence the 

 general health. 



Even if further investigations should 

 fail to confirm this result, it is my personal 

 feeling that occupied rooms should be kept 

 free from noticeable odors as a measure of 

 public decency if not of public health. 

 The cleanliness which results from the 

 habit of bathing, except for the washing of 

 the hands before eating, has, so far as I am 

 aware, no important sanitary results. Just 

 as the people who have been in a close room 

 do not notice the odors which have accumu- 

 lated during their occupancy, the person 

 unaccustomed to bathing is unconscious of 

 the effect produced, yet common decency 

 rightly demands both bodily cleanliness and 

 fresh air. 



Eecent research has, on the whole, 

 strengthened rather than weakened the 



arguments for ventilation. It has shown, 

 however, that the physical quality of the 

 air as well as its amount must be consid- 

 ered, and that a room supplied with air at 

 the room inlet which will explode a ther- 

 mometer registering to 125° (which hap- 

 pened to the instrument of one of my in- 

 vestigators in a New York City school) is 

 not well ventilated, however many cubic 

 feet of air may enter it. 



The thermometer is the first essential in 

 estimating the success of ventilation. Tem- 

 perature standards must come into general 

 use and a rise above 70° must be recognized 

 as a sign that discomfort is being produced 

 and efficiency decreased and vitality 

 lowered. The carbon dioxide standard is 

 still of value, however, as ordinarily a 

 measure of the air change which is required 

 to carry off both heat and odors; and the 

 mechanical standard of thirty cubic feet of 

 air per minute per capita as the amount 

 necessary to supply in some way if an 

 occupied room is to remain cool and fresh 

 is still of general application. 



The question of humidity is perhaps the 

 most important one which remains to be 

 solved before the practise of ventilation 

 can be placed on a sure basis. A lack of 

 humidity, as Professor Phelps has pointed 

 out, makes hot air feel cooler and cold air 

 feel warmer. Extreme dryness per se, 

 however, at high or moderate temperatures, 

 is believed by many to be in itself harmful, 

 conducing to nervousness and restlessness 

 and producing injurious effects upon the 

 membranes of the nose and throat. There 

 is, unfortunately, no solid experimental evi- 

 dence upon this point, and this is one of the 

 most important subjects which the N. T. 

 State Commission hopes to be able to study 

 during the coming year. 



It is a foolish empiricism which main- 

 tains that outdoor air as Nature makes it 

 is necessarily the final word in air eon- 



