TESTING AIRMEN'S NERVES.

Taranaki Daily News, 5 February 1917, Page 7

TESTING AIRMEN'S NERVES.

NEW FRENCH SYSTEM. HOW FITNESS IS ENSURED. The Figaro has just given an interesting account of the new and highly ingenious method of determining whether a man is physically fit to become an airman. This method is now being practised in Paris, notably at the hospital in the Grand Palais, under the superintendence of I)rs. Jean Camns and Netter. Candidates for the French Flying Corps have always, of course, been medically examined to make sure that their principal organs are sound, hut this does not go far enough. An essential quality in a successful airman is rapid perception, coupled with instant decision. Vi hile the sapper counts in minutes and the bomber in seconds, a fraction of a second may make all the difference to an airman.

In the case of every human being there is a brief interval between the instant at which an object becomes visible and the instant at which this visibility is realised by the nervous system. In touch and hearing there is also this period of transmission, which varies according to the condition of the subject's nervous ststem; and these periods can now not only be ascertained, but actually measured in hundredths of a second.

A further development of the same idta enables the examiner to find oi't what may be called the candidate's emoticiinl temperature, or, in other wonU, lno ability to resist sudden shock.?. His self-eon 1 '»i or sanr-'ioid, tan be. measured just ae exactly as his pc.'c;.>:lL><]ity.

HUNDREDTHS OF SECONDS. The candidate is placed in front of a table on which is an electric chronompter, having a dial'divided into hundredths of a second. The hand, which go« right round the dial in a second, is held motionless by a electric current. As soon as the current is interrupted the had is propelled by clockwork until the current is restored. 'The examiner and the candidate each holding an instrument, the slightest pressure on which stops the current and releases the diai hand, the candidate is told to look at the dial and press his interrupter immediately lie sees the hand move.

It has been found by experiment that, in the case of an ordinary good subject, this process should take about nineteenhundredths of a second and the candidate's perceptiveness is judged according to this standard. Many men who havo come up for this examination, believing themselves physically well qualified to become fliers, have failed to pass this test, the remorseless hand having consistently registered 25 or 30 hundredths of a second against them. These men will never be successful airmen, becauw> the point at which they waul, to comu down will present itself to them just a quarter of a second too late. After the visual tost comes the auditive. The candidate is told to 6hut his eyes and press the interrupter as soon as he hears the sound of a hammer striking the table. The sense of touch is tested by a slight blow on the nape ot the neck. In both these cases the reaction is more rapid than in the visual test, the average co-efficient being 14 instead of 19.

THE 'TELL-TALE LINE. The emotional tests are more complicated. On a table is a revolving drum covered with a sheet of smoked paper on which lines are traced by three electrically driven needles. One of these is connected with an instrument in the candidate's right hand, nnd registers the movements of the hand when a slight shock is administered. The second needle is connected with a band round the candidate's chest, and records his inspiration on the smoked paper. The third needle follows the movements of a very delicate instrument which presses i'ii the vaso-motor nerves of the left hard. After the. drum has revolved for a few seconds, the candidate, is told to shut his eyes, and a pistol is fired close to his bend. If his nerves are thoroughly sound the white lines traced by the three needles on the, paper will show no deviation. Tf, on the other hand, zigzag's on the paper show that when the pistol was fired his respiration was affected, his hand wavered, and his vasomotor nerves shrank ever so slightly (showing that he turned pale), the examiners can only reject him as unsui'. able.