122 PHYSIOLOGY OF INDUCED HYPOTHERMIA 



167. Foster, M. A., Foster, R. C, and Mejer, R. K. : Hibernation and the endocrincs, Endo- 



crinology 2^; 603, 1939. 



168. Johnson, G. E., and Hanawalt, V. B. : Hibernation of the thirteen-lined ground squirrel, 



Citelhts tridecemlineatns (Mitchill). IV. Influence of thyroxin, pituitrin and desiccated 

 thymus and thyroid on hibernation, Am. Nat. 64: 272, 1930. 



169. Vidovic, V. L., and Popovic, V. : Studies on the adrenal and thyroid glands of the 



ground squirrel during hibernation, J. Endocrinol. 11: 125, 1954. 



170. Prosser, C. L. : Comparative Animal Physiology, W. B. Saunders Co., Philadelphia, 



Chap. 10, 1950. 



DISCUSSION 



Dr. Alan C. Burton: I would like to ask whether Dr. Lyman has verified the 

 older observations about there being some abnormality in the hibernating animal of 

 magnesium to potassium or sodium ratio, and whether he thinks this could be one 

 tissue fact or biochemical fact which might be responsible for the different tissue 

 states. 



Dr. Lyman: I haven't done anything with magnesium. My personal feeling alDOut 

 any ionic imbalance is that if this is the situation it must have to be corrected the 

 mintite the animal starts to wake up from hibernation. I can't visualize exactly how 

 this can occur. Even though there have been various reports concerning magnesium, 

 some saying that it is high and some saying that it is normal, I haven't measured it. 



Dr. Allen D. Keller: I would like to comment a little further about the presence 

 of shivering in hibernation. The old literature never mentions whether there is 

 shivering or not. I see you did demonstrate shivering in the woodchuck. 



Dr. Lyman: During hibernation? 



Dr. Keller: When they come out. 



Dr. Lyman: They do shiver violently, particularly in the anterior end, as they 

 warm to, say, 15 or 20° C. Also I have seen woodchucks shiver during hiberna- 

 tion every once in a while. They make gross movements and then seem to have a 

 slight tremor. This is in the steady hibernating state. I have never seen that in ham- 

 sters. They curl up in a little ball and look completely dead until you pick them up, 

 and then you see their whiskers move. That is all that seems to be happening. 



Dr. E. Calkins: I was much interested in your observation on the serum epine- 

 phrine level during hibernation. Do you know what can be done to non-hibernators 

 to stimulate their hibernation ? We cannot change the diaphragms or tissues, but is it 

 possible that administration of epinephrine competitors might enable non-hibernators 

 to get along better at a low temperature? Do you know of anybody who has done 

 that? 



Dr. Lyman: Not as far as I know. It is worth while trying, certainly. The trouble 

 is that there are side effects with almost any epinephrine competitors. 



Dr. Calkins: If it could be administered without much difficulty, as I know you 

 can with humans, and I am sure to animals, and prevent the epinephrine response 

 to cold, you would avoid some of these complications that we are hearing about. 



Dr. George E. Burch: I would like to know if you studied the peripheral circu- 

 lation which shows the heart declines in rate as hibernation starts. Does the blood 

 shift from the peripheral vessels into the body? 



