286 BIOLOGICAL PROBLEMS 



conclusions: That carbon dioxide up 100.35 P er cent 

 exerts no appreciable effect on mental capacity; that 

 temperatures above 65 F., independent of other air 

 conditions, give rise to definite subjective symptoms 

 (slackness and inattention in some, headache in others, 

 and deterioration in mental work); that these symp- 

 toms do not appear at 65 F. if the air is kept in 

 gentle movement by a fan in the room, and that at 

 higher temperatures the above symptoms are amelio- 

 rated by such movements of the air; that with tem- 

 peratures of 70 F. and over, other factors being 

 normal, there are marked symptoms and very evident 

 deterioration in mental alertness and accuracy; and 

 that relative humidity does not affect the mental capa- 

 city of children at low temperatures (below 65 F.), 

 but an increase of humidity appears to aggravate the 

 effects of higher temperatures in reducing working 

 capacity. Observations in America (Boston) confirm 

 certain particulars of these findings. 



The New York State Commission on Ventilation 

 has recently conducted experiments which, in the first 

 place, have been directed towards ascertaining the 

 effects of high temperature. The physical tests 

 selected were (a) the number of times a dumb-bell 

 could be raised to a given height, and (b) the work 

 registered by a Krogh bicycle ergometer (a standard 

 bicycle with an artificial resistance). The mental 

 tests consisted of (a) the naming of colours, (b) the 

 cancellation of given letters in a large group, and 

 (c) the addition of numbers, mental arithmetic, and 

 type-writing. 



The results of these experiments indicate that over- 

 heated rooms are not only uncomfortable, they also 

 produce well-marked effects on the heat-regulating 

 mechanism and circulatory system, and materially 

 reduce the inclination (though not the power) for 



