HETEROTHEPMY IN HOMEOTHEEMS 



The report of sensation involves complex neural mechanisms 

 which we cannot analyze physiologically. Since only part of the hand 

 or of a finger is cooled and we cannot control effectively the amount 

 of tissue cooled, we suspect that the regular thresholds observed in 

 day after day tests indicate that cooling of the hand affects the local 

 peripheral agents of sensation. But we are still only measuring a 

 threshold and not the sensation that is involved in our estimation of 

 the physical dimensions of stimulation. It is nevertheless interesting 

 to consider this test an illustration of the integration of heterother- 

 mous tissues in an individual organism. Certain characteristics of 

 the external world must be appreciated in constant dimensions, and 

 yet the signals for those dimensions are submitted through peripher- 

 al transducers that change characteristics as the tissues which con- 

 tain them warm and cool. 



In comparison with thenaturaladaptationof animals to cold, the 

 best physiological adaptation developed in people is only of small 

 magnitude, and cultivated human habits and economy provide the 

 main protection from cold. Some people resident in cold climates 

 are motivated to utilize to the utmost their small physiological a- 

 daptability to cold. They find it worthwhile to practice exposure that 

 seems very unpleasant for us who are accustomed to sheltered urban 

 life. We face the test of cold with anxiety and respond in the irregu- 

 lar manner that characterizes untrained physiological reactions. 



Power and equipment from foreign sources are used to relieve 

 soldiers and transient workers in the north from adaptation to its 

 cold climates. In each successive war in history power and tech- 

 nology have improved the protection of armies from cold and en- 

 abled them to live and move effectively in any climate and on any 

 terrain. In spite of improving protection from the weather it is sur- 

 prising that in every war winter cold blocks operations in the field 

 and continues to be a major cause of injury. The reason lies in de- 

 pendence upon power susceptible to accidental disruption. Military 

 tactics aim to damage the enemy's vulnerable heating system or to 

 lead him into a position where its effectiveness diminishes. Then 

 troops accustomed to shelteringwarmth are immobilized by the pro- 

 tection that has left them inexperienced in cold, while those less de- 

 pendent upon artificial warmth may retain a small but decisive abil- 

 ity to maneuver. 



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