PHYSIOLOGICAL ASPECTS OF FLYING 209 



that this acuity of vision is considerably greater in 

 some persons than others. Tests for this power of 

 vision are accordingly being made. 



Good hearing is also of importance, not only for 

 ordinary apparatus such, as the telephone, but also 

 because a pilot should be able to judge to a certain 

 extent whether his engine is running well or not; 

 as already mentioned, he derives information from 

 the singing of the wind through the wires. For 

 many pilots, however, it is perhaps as well for them 

 not to have too keen an appreciation of the running 

 of an engine by its note, but only whether it is run- 

 ning really well or really badly. 



Finally, in addition to good vision, hearing, and 

 sense of touch, it is important that the aviator should 

 possess good "reaction times", which is to say that 

 he should translate the impulses received from the 

 above-named senses into the appropriate necessary 

 actions in at least normal average time, and, in the 

 case of the scouting pilot, in times less than normal. 



The importance of such reactions is seen in all 

 stunting, since, with the aid of these senses, the avia- 

 tor, by appropriate movement of the joystick, must 

 complete his evolution, and any delayed response may 

 result in difficulties or even in disaster. 



Such, in brief review, are the main physiological 

 aspects of flying. The manner in which such know- 

 ledge is applied to the efficient care of the airman 

 cannot be dealt with here. Suffice it to say that the 

 keynote of such care is preventive, and, since physi- 

 ology is the servant of medicine, much use is made of 

 the methods here reviewed in determining the nature 

 of any disability which may develop. By more 

 elaborate methods disability at high altitudes may be 

 investigated and its true nature sought. 



The care of the flying officer is a great privilege. 



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