PHYSIOLOGICAL ASPECTS OF FLYING 207 



stimuli such as burning, unexpected noise, or smell, 

 but also to psychical stimuli, such as apprehension, 

 questions, and thoughts, pleasant and unpleasant. 

 From many experiments made on various individuals 

 it has been found that there is a marked difference 

 in emotive response, and it would be of interest 

 to know the nature of the response given by the 

 examination of a series of experienced and successful 

 pilots. 



The successful sportsman possesses not only sound- 

 ness of heart and wind but also valuable reflexes con- 

 nected with delicate muscular co-ordination, acuity 

 of vision and hearing, all necessary attributes in a 

 successful flying officer. The capable horseman is 

 likely to possess the correct lightness of hand to con- 

 trol in delicate fashion the joystick of the aeroplane. 

 He has probably also acquired, by cutaneous and 

 muscle sense, especially from the buttocks, a lively 

 apprehension of the position of his body in relation 

 to his seat. 



The question of balance is, however, a rather diffi- 

 cult one. In Allied countries much attention has 

 been directed to the examination of the labyrinthine 

 mechanism of the internal ear. This mechanism con- 

 sists mainly of three pairs of semicircular canals 

 filled with fluid; the sensations from these yield in- 

 formation as to the position of the head in regard to 

 the three planes of space. Although practised in this 

 country, such detailed examination has not had so 

 great a vogue, since it is realized that the impulses 

 from the labyrinth must always be associated in flying 

 with the sense of vision. By vestibular impulses 

 alone the aviator cannot tell the position of his machine 

 in regard to the earth, and is likely to emerge from 

 a thick cloud upside down. Generally speaking, the 

 airman derives most of his knowledge in regard to 



