112 CONTEMPORARY SCIENCE 



wireless telephone receivers on his ears, a combined tele- 

 phone transmitter and oxygen inhaler over his mouth, and 

 a padded helmet on his head ! 



The importance of determining the aviator's inherent 

 power of resistance to oxygen deficiency, if he is to be 

 even for a few moments without an oxygen inhaler, is 

 demonstrated by the results of the routine examinations 

 made with the rebreathing apparatus in the laboratory. 

 These results show that 15 to 20 per cent, of all the men 

 who pass an ordinary medical examination are unfit to 

 ascend to the altitudes now required of every military 

 aviator. On the other hand these tests pick out a small 

 group of 5 to 10 per cent., who, without apparent im- 

 mediate physical deterioration, withstand oxygen defici- 

 ency corresponding to altitudes of 20,000 feet or more. 



It is particularly interesting to note that when the re- 

 breathing test is pushed beyond the limit that the man 

 can endure, be it the equivalent of only 10,000 or 25,000, 

 two different physiological types with all gradations be- 

 tween them are revealed. The fain'ting type collapses 

 from circulatory failure and requires an hour or two to 

 recover. Often the heart appears distinctly dilated. The 

 other and better type, on the contrary, goes to the equiva- 

 lent of a tremendous altitude on the rebreathing appara- 

 tus and loses consciousness, becoming glassy-eyed and 

 more or less rigid, but without fainting. When normal 

 air is administered such men quickly recover. 



Perhaps I ought to say at least a few words regarding 

 the other aspects of the work at Mineola: for example 

 the valuable psychological investigations and the contro- 

 versy over the rotation tests, which have figured so largely 

 in our medical journals of late. It seemed best, however, 

 to confine myself this evening to my own special field. 

 Nevertheless I cannot suppress a public expression here 

 of my sympathy for the brave and able scientific men in 

 the psychological group at Mineola, who insisted on in- 

 vestigating the validity of the rotation tests. I am sure 



