BABBOTT 



zero (Davis, 1943). As you realize, the resultingdisability was often 

 permanent, with loss of fingers, toes, or even a whole foot. Less 

 severe cases required hospitalization ranging from a few days to 

 many months. So there can be no doubt about the importance of 

 direct injury by short-term exposure to cold, especially in military 

 populations. 



But a long-term direct effect of environmental temperature on 

 evolving races of man has also been postulated. Howells points out 

 that ethnic groups arising in the warmest and coldest climates seem 

 to have developedaphysiqueandbody mass which permits the maxi- 

 mal dissipation or conservationof heat(Howells,1960). He contrasts 

 the large surface area of the Sudanese tribesman with the squat, 

 compact build of the pure-blooded Eskimo, and discusses the ad- 

 vantages of each with respect to the physiologic demands of his 

 immediate surroundings. Thus, cold seems to have a direct effect 

 not only on men as individuals, but even on the development of the 

 race itself. 



However, the purpose of this symposium is not to discuss cold 

 injury per se, but rather to explore some of the more subtle in- 

 fluences of cold on infectious agents and host responses. In the 

 laboratory, as we will be hearing, it is possible to raise animals, in- 

 fect them and measure their reactions, all under hypothermic con- 

 ditions. Likewise, we may propagate the agent at any point on the 

 temperature scale compatible with its survival. Yet Dr. McClaughry 

 has just pointed out the difficulties encountered when we try to 

 undertake similar observations on human populations living in a 

 setting rampant with uncontrolled and even unrecognized variables. 



Part of the trouble is that under natural conditions, both men and 

 infectious agents do their best to avoid the less than optimal environ- 

 ment imposed deliberately in the laboratory. We can set up an ex- 

 perimental hypothermic stress and force mice to a compensatory 

 physiologic adaptation, one manifestation of which maybe a reduced 

 capacity to resist infection. But when it gets cold at Wainwright or 

 Fort Yukon, the inhabitants merely put on an extra parka or add 

 more fuel to the stove. Only occasionally is a hunter caught on an 

 ice floe or an airman down on the tundra in circumstances where 

 he experiences the same sort of stress required of the laboratory 



