HETEFOTHEPMY IN HOMEOTHEBMS 



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In these studies we found fingertemperatures were about 33 C 



when the subject was supine at a room temperature of about 20 C. 

 After stable measurements were attained at room temperature, the 

 finger was immersed into a stirred ice bath. At this point, of course, 

 a typical "Lewis response" occurs; that is, a rapid cooling to 

 approximately the temperature of the bath, followed by a period 

 of spontaneous rewarming to about 10 C to 12 G. I think that this 

 is an almost classical response and anyone can reproduce the 

 experiment using similar test conditions. This is the t3^e of res- 

 ponse that we find in all of the subjects in non- anxiety states. In 

 superimposing the effects of anxiety, however, we can change this 

 pattern to one where the cooling phase is prolonged to 25 minutes 

 after the initial immersion of the finger into the ice bath. This is to 

 be contrasted to the "unstressed" subject, where the spontaneous 

 vasodilation normally occurs in about 7 minutes. This, I think, would 

 probably indicate that there is a functional integrity of at least the 

 efferent nervous components in the peripheral portion of the finger 

 at these temperatures. Incidentally, the temperature that I am dis- 

 cussing is, of course, the temperature at the thermocouple taped to 

 the surface of the finger. It indicates very little, if anything, about 

 temperatures deeper in the finger where one may expect to find the 

 sensory endings and where you may also expect some peripheral 

 vascular changes to come about with mild degrees of adaptation or 

 cold acclimatization. 



We became interested in this phenomenon as a possible test 

 site for induced variations in peripheral vascular responses with 

 local chronic cold exposure in the same individual. The condition- 

 ing phase in our series of experiments consisted of immersing the 

 same portion of the right index finger in a stirred ice bath for 20 

 minutes each timefor one month; different groups of subjects under- 

 went two, three, or four such exposures each day. In the group of 

 subjects that showed the greatest difference in response to the finger 



immersion in stirred ice water, we found the finger temperatures 



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cooled to only 10 C in the bath, compared to C in the control 



experiments. The first thing that we saw was an earlier initiation 



of the rewarming phase after about one week of cold conditioning. 



We also carried out digital calorimetric measurements when the 



finger was maximally vasodilated in the bath and found a statistically 



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