358 



SCIENCE 



[N. S. Vol. XLII. No. 1080 



Symposium with Section K, A. A. A. S. 



Feiitilation 



Under the supervision of C.-E. A. Winslow 



Ventilation in Its Relation to Air-borne Diseases: 



De. a. C. Abbott. 



In several hospitals for tlie care of contagious 

 diseases in England, Framee, and in one in partic- 

 ular in this country, it has been conclusively dem- 

 onstrated that certain of the so-called ' ' air-borne ' ' 

 diseases of different natures may be treated side 

 by side in the same ward without fear of greater 

 transmission than commonly occurs when they are 

 treated in separate wards. Obviously such observa- 

 tions justify grave doubts of the aerial conveyance 

 of disease. 



Though we do not know the causative agents of 

 the majority of the so-called "air-borne" diseases, 

 yet presumably they are particulate and never 

 gaseous in nature. Therefore, they behave in the 

 air, when they get there, just as do other sus- 

 pended particles. 



Erom iaformation obtained through the study of 

 another phase of the subject we know that a num- 

 ber of diseases may be conveyed through the air, 

 but here it is always through the agency of insects 

 acting as vectors or as hosts for the infective para- 

 sites. This, obviously, has more to do with wire 

 screens than with ventilation. 



In the Ught of the foregoing, I do not believe 

 that ventilation has anything whatever to do with 

 either the transmission of the so-called "air- 

 borne" diseases, or the lessening of their trans- 

 mission, and I am further of the opinion that 

 transmission by way of the air, strictly speaking, 

 is of infinitely less importance than transmission 

 by animate and inanimate carriers that have been 

 in intimate contact with the patient. 

 Some Fundamental Physical Factors in the Prob- 

 lem of the Control of Atmospheric Environment: 



E. B. Phelps. 



The physical problem of heat dissipation from 

 the body is conditioned externally by four prime 

 factors; temperature, humidity, velocity of air 

 movement and radiation. Experimental determi- 

 nation of the mutual relationship and individual 

 influence of the first three of these is reported. 



A simple air conditioning apparatus furnished 

 the experimental air at temperatures of 8° to 40° 

 C, relative humidities 30 per cent, to 90 per cent, 

 saturation and velocities up to 250 cm. per second. 

 The heat loss was determined from a continuously 

 moist skin surface exposed to these various air 

 conditions. The surface formed the only exposed 

 portion of a calorimeter in which accurate thermo- 



control was provided, the actual heat lost being 

 compensated electrically and determined by noting 

 the volume of gas produced electrolj^ically by the 

 passage of the same heating current through di- 

 lute sulphuric acid. The results between 20° and 

 40° are expressed by the f llowing equation: 



c, fviM72{i6.7 — p) +.00294(37 — *)]. 

 c, is the heat loss in calories per minute per 



sq. centimeter. 

 V, the velocity of movement in centimeters per 



second. 

 p, the absolute humidity in milligrams per 



liter, and 

 *, the temperature Centigrade. 



Below 20° a complicating humidity relation was 

 developed and at lower temperatures this relation 

 reversed the one found above, so that increasing 

 humidity brought about increasing heat loss. 

 This latter relation has not yet been formulated. 



Standards of Ventilation in the Light of Recent 



Research: C.-E. A. Winslow. 



The investigations of the New York State Com- 

 mission on Ventilation have indicated that even 

 quite extreme conditions of heat and humidity 

 (86° with 80 per cent, relative humidity) have no 

 measurable effect upon the rate of respiration; 

 dead space in the lungs; acidosis of the blood; 

 respiratory quotient; rate of digestion and rate of 

 heat production (both measured by oxygen con- 

 sumption) ; protein metabolism (measured by de- 

 termination of creatinine in the urine) or skin 

 sensitivity. 



On the other hand, the working of the circula- 

 tory and heat-regulating machinery of the body 

 was markedly influenced by even a slight increase 

 in room temperature, as, for example, from 68° to 

 75° with 50 per cent, relative humidity in both 

 cases. In a hot room (86° — 80 per cent, relative 

 humidity) the rectal body temperature usually 

 rose during the period of observation; in a warm 

 room (75° — 50 per cent, relative humidity) it re- 

 mained on the whole about constant; in a cool 

 room (68° — 50 per cent, relative humidity) it fell. 

 The average body temperatures attained under 

 these three-room conditions were 37.41°, 36.99° 

 and 37.73°, respectively. The increase of heart rate 

 on passing from a reclining to a standing posi- 

 tion became greater by an average of 7 beats dur- 

 ing a sojourn in the hot room, while it became less 

 by an average of 3 beats in the warm room and by 

 an average of 7 beats in the cool room. 



Elaborate psychological tests failed entirely to 



