MOUNTAIN SICKNESS 217 



drinking debauch he executed only 67 lifts, and his pulse rose 

 from 56 to 110, his respiration from 18 to 32. 



To show the influence of fatigue on the induction of mountain 

 sickness, P. Regnard placed two guinea-pigs under the bell of 

 the air-pump, one at rest and the other in a tread-wheel which 

 was rotated by an electric motor. This guinea-pig was com- 

 pelled to run up the wheel, and became affected at 3000 m. 

 and tumbled on its back at 4600 m., while the resting animal 

 was not affected until the barometric pressure corresponded 

 to 8000 m. 



To explain the effect of muscular work, we must turn to the 

 study of the respiratory exchange. Zuntz and Schumberg have 

 compared the consumption of oxygen in walking on the flat 

 and in climbing. The subject carried a gas-meter on his back 

 connected with a mouthpiece which was provided with inspira- 

 tory and expiratory valves. A sample of the expired air was 

 collected by the rotation of the meter by a special device, while 

 the total amount was measured by the meter. The percentage 

 composition of the inspired air was calculated from readings of 

 barometer, temperature, and humidity. Analysis of the expired 

 air and the readings of the meter together gave the C0 9 output 

 and the 2 intake, and the respiratory quotient was calculated from 

 these. The estimation of the urinary nitrogen excretion gave the 

 proteid metabolised, and the respiratory quotient indicated the 

 share which fat or carbohydrate respectively took in the meta- 

 bolism. The nitrogen-holding nucleus of the muscle substance 

 is not used except under conditions of insufficient food or over- 

 strain. Zuntz calculates that 1 litre 2 is used in the combustion 

 of 1 grm. proteid and yields 4476 Cal. ; of fat, 4-686 Cal. ; of starch, 

 5-047 Cal. After a meal carbohydrate is burnt, and the Caloric 

 worth is found by multiplying the litres of 2 consumed by 5. 

 Before breakfast or fasting body fat is used, and the Caloric worth 

 is obtained by multiplying by 4'8. 



For walking on level ground the average consumption of 2 

 per kg. body weight per km. of march averages 100-110 c.c. 2 . 

 On increasing the pace from 58 to 140 m. per min. the 2 use was 

 doubled. Climbing up 100 m. in a walk covering 1 km. likewise 

 doubled the 2 use. Difficulties in the way, steep ground, un- 

 practised movements, greatly increase the 2 consumption. A 

 sore foot increased it by 18 per cent. Fatigue likewise increased 



