THERMORECEPTOR PHYSIOLOGY 
DR. HENSEL: Yes, that is right, but the general shape of the 
curve is the same in all experiments. This can be proved by apply- 
ing standard cold stimuli during the transient stop of the discharge 
after rewarming. The longer the period of time after the cessation 
of the discharge, the more effective the cold stimulus. When plotting 
the effect of the standard cold stimulus against time, the resultant 
curve is the mirror image of the overshoot during cooling. But, of 
course, the impulse frequency cannot be less than zero. 
DR. MINARD: Is there a rate of temperature change so slow 
that you do not observe the phasic discharge? 
DR. HENSEL: Yes. I think it is not even necessary to make the 
change very slow because this partial adaptation occurs rather 
rapidly. A slow linear change of temperature with time throu^ the 
whole temperature range will give very much the same frequency 
diagram as that for the steacfy discharge shown in Figures 9 and 13. 
DR. MINARD: There have been some reports that individuals 
who have been exposed to gradual increase in cold, such as when 
they have been lying outside in a sleeping bag, have died, apparently 
without even waking up during the course of this cooling process; and 
the assumption was that the rate of change was so slow that this 
was not perceived as a cold stimulus. 
DR. HENSEL: I think this concept contains some truth because 
the maximum frequency obtainable by rapid cooling is 15 times 
higher than that obtained during slow cooling or at constant temper- 
ature. 
COL. QUASHNOCK: Dr. Hensel, would the subject report any 
residual changes in sensation either transient or permanent after 
recovery? 
DR. HENSEL: Well, most of the subjects reported a decrease 
in sensitivity in an area about 2 cm in diameter. It was no complete 
anaesthesia but paraesthesia or hypaesthesia. In one subject there 
was no change at all because of the overlapping.- 
COL. QUASHNOCK: How many subjects have been done? 
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