HOW WE KEEP OUR BALANCE.

Star (Christchurch), Issue 12572, 8 March 1919, Page 12

HOW WE KEEP OUR BALANCE.

Onr sense of balance is due not merely to the semi-circular canals of our inner ears, but to three main sensory sources. These are the aforesaid canals, our eyes and the pressure sense which is a combination of impressions received from our vertebrae, the muscles of our hacks and necks, and 'the weight of our internal organs. Eh- .Percy Fridenburg, the ophthalmic surgeon of Lebanon Hospital, and junior surgeon of the New York Eye and Ear Infirmary, points out in the journal of the American Medical itesociation that an examination in equilibrium of candidates for aviation that is confined to their reaction to impressions on the nerves of the ears and that neglects the other two just as important factors is not likely to save/them from falls. That dizziness may be produced solely by sight is patent to everyone who has experienced it on looking down from a great height, Dr Fndenburg says: lar illumination and motion of objects alone may cause dizziness and confusions, as seen in the‘common or field variety of " movie ” headache or dizziness. A swinging mirror may cause a most marked sea-sickness, which, itself the classical example of vertigo, is often relieved most effectively by excluding visual impressions merely by closing the eyes." He quotes remarks of aviators who say that when thev get. into thick clouds they cannot tell whether they pe on a level or not, and urges that in the training of airmen their reactions to unusual visual conditions ho observed carefully by their instructors.