SUPERCOOLINC AND FREEZING— ANDJUS, EO\T.LOCK ano SMITH 141 



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Fig. 9. — Effect of the duration of suspended animation in rats maintained at 0° C. of body- 

 temperature on the rate of recovery. Number of rats : whole bar — total number of individuals 

 in an experimental group ; black areas — long-term survivors ; double shaded areas — dead within 

 10 days; simple shaded areas^dead within 24 hours; white areas — failed to revive. (Data from 

 Andjus, 1955.) 



After effects. The physiological changes recorded after normal body tempera- 

 ture is re-established differ greatly according to the level of hypothermia reached. 

 Animals were not maintained longer than two hours at a given level of hypothermia 

 in experiments referred to here. Rats cooled not lower than 15° C. re-establish 

 their normal metabolic rate, thermoregtilation, and blood constitution soon after 

 normal body temperature is reached again. Blood sugar concentration, for instance, 

 reaches normal values by the time the normal body temperature is regained, regard- 

 less of whether the latter is reached in 30 minutes or in two hotirs. Psychological 

 tests showed no impairment of learning capacity and retention (Andjus et a!., 

 1955). It is important, however, to note that some changes which were not elicited 

 during cooling, appear on rewarming. For example, the marked soditim retention by 



