238 



PHYSIOLOGY OF INDUCED HYPOTHERMIA 



5 5/ 



RAT LIVER PERFUSION ^^^3 



Fig. 2. — Protocol of liver perfusion experiment 55-93, showing effects of cooling to 32° C. and 

 to 25° C. upon blood flow, blood glucose, and bile flow. 



The hypothermic rat Hver is capable of responding to choleretic stimuli at 30° C, 

 and in general also at 25° C' The relative increase in bile How following dehydro- 

 cholate at 25 to 30° C. is as great as that at 38° C. though the absolute response — 

 measured as extra bile volume — is, of course, reduced in proportion to tlie basal 

 bile flow. At 25° C or lower we ha\e at times seen a curious ])lu'nonuMion whicli 

 we have dubbed the "freezing in" of the choleretic effect. In such cases there will 

 be a minimal choleretic response at the low teniperatin"e btit a very marked over- 

 .shooting of bile flow rate on rewarming. Since this res])onsc is probably related to 



