June 5, 1919. No. 6894, second lieutenant, pilot, twenty-nine, single, ranch 

 manager. 



One hundred hours flying, one crash. 



Physical condition good but had a slight headache. 



Run was preceded by 13 minutes' rebreathing during which the oxygen was 

 replenished as consumed. 



Only moderately fast but quite accurate. In the 14th minute he showed 

 distinct initial impairiment of muscular coordination and attention. After 

 the llth series, he showed progressive decrease in both speed and accuracy until 

 the end. He was taken off for inefficiency at 37:45. He was still making some 

 correct substitutions but was finding the operations, including the \\riting, very 

 slow and difficult. A controlled drop of diastolic blood pressure was occurring 

 during the last few series. 



220 



