MILAN 



and that skin temperatures were low. They postulated a more effec- 

 tive vasomotor control than that of civilized individuals. After the 

 ingestion of raw meat, the SDA of protein resulted in an 80% rise in 

 metabolism after 5 hours. The RQ was measured as 0.7 in fasting 

 subjects and moved toward unity after a meal. 



Morrison (1957) used a StoU-Hardy radiometer to measure skin 

 temperatures in sleeping aborigines at Haast's Bluff in Central 

 Australia. He concluded that the aborigines had a lower sensitivity 

 to cold, which allowed them to sleep despite low body temperatures. 



Scholander et al. (19 58) studied the Pitjandjara tribe which in- 

 habits the deserts of Central Australia. Two natives and two Euro- 

 pean controls slept naked "proper bush style," lying on the ground 

 between two fires in winter. Neither Australians nor Europeans ele- 

 vated their oxygen consumption, although the Europeans were uncom- 

 fortable and did not sleep well. The natives stoked their fires three 

 to ten times while the Europeans stoked eleven to fourteen times. 

 The natives tolerated a lower average skin temperature. 



In a second experiment four Europeans and six natives slept 



naked in a bag of 1.9 clo insulation on a canvas cot under a thin 



^ o o 



radiation shield. Night temperatures were between 5 C and C. 



The metabolism of the natives fell below basal values during the 

 night, whereas the Europeans elevated their metabolism by bursts 

 of shivering. The natives slept, while the European controls were 

 kept awake by cold feet, although the natives had lower skin tempera- 

 tures. It was concluded that the natives had adapted both their tech- 

 nology and physiology to withstand chronic cold exposure. 



Hammel et al. (1959) returned to study the Central Australian 

 natives in summer to see if the differences reported by Scholander 

 et al. (1958) were seasonal. In addition, natives from the tropical 

 north coast with a history of little cold exposure were studied. Eight 

 male Pitjandjara, nine male tropical natives, and seven male Euro- 

 pean controls were exposed during sleep in a 1.7 clo bag in a refrig- 

 erated meat van for 8 hours at 5 C. The metabolism of the Pitjand- 

 jaras was lower than that of the European controls. The tropical 

 natives were intermediate in metabolic response. The Pitjandjaras 



350 



