292 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1953 



arm is reduced to but 1.5 percent of the body's total at higher tem- 

 peratures. The amount of blood that flows through 100 cc. of finger- 

 tip tissue falls from a maximum of 120 cc, to 0.2 cc. per minute (Day, 

 1949) . The arm itself becomes an insulator in depth. 



At an air temperature of 73° F. a naked American with a rectal 

 temperature of 97° will show the following skin temperatures : head, 

 94° ; trunk, 93° ; hands, 86° ; feet, 77°. Deep thermocouple work has 

 shown that the hands and wrists chill to the bone literally. How- 

 ever, when the temperature of the extremities falls below a point 

 between 41° and 50° F., vasoconstriction ceases, and peripheral blood- 

 flow is accelerated, to keep the extremities from freezing (Spealman, 

 1949a, p. 236). Wliat this means racially is that a person of north 

 European ancestry can afford to have big bony hands which help keep 

 him cool in hot weather, because at the winter temperatures at which 

 he operates, particularly when clothed, the size of his hands makes no 

 difference in heat economy; they are simply shut off from the heat 

 system, like an empty room. 



It is a matter of casual observance that most Mongoloids have small 

 and delicate hands and feet, short distal segments of both upper and 

 lower limbs, and short necks. However, recent studies of the Eskimo 

 have shown that despite expectation these people have large hands 

 (Rodahl and Edwards, 1952). It is believed, although the material 

 proving this has not yet been published, that racial differences in 

 venous patterns exist, which would account for the Eskimo hand as 

 well as for the ability of the Australian aborigine to sleep in the cold 

 without clothing. 



Turning to the Eskimo foot, which is small as expected, it is common 

 knowledge that his excellent boot keeps this extremity warm, as 

 long as it is dry. Water can leak in through the stitch holes if the 

 sinew is not preswollen (Spealman, 1949b; Wulsin, 1948), and it can 

 also come from sweat induced through exertion. A wet boot affords 

 little insulation, and some Eskimos freeze their toes. Similarly the 

 hand is here a liability; as Quartermaster Corps researchers have 

 shown, it is almost impossible to keep a hand warm in the best of 

 mittens when the body is at rest outdoors in very low temperatures 

 (Belding, 1949; Van Dilla, Day, and Siple, 1949, p. 384). Eskimos 

 bring their arms and hands in next to the body skin, leaving sleeves 

 dangling, when they can. 



Ears, nose tips, and other protrusions need special protection ; with 

 the fall of the glass the amount of blood sent to the ears increases 

 greatly, and a relatively gi-eat loss occurs at this vulnerable point. 

 Polar and subpolar peoples are invariably described, in the prime 

 of the individual, as being well equipped with subcutaneous fat. This 

 fat is especially well developed on critical spots, such as the cheek, 



