UNANESTHETIZED POIKILOTHERMIC DOG— KELLER 79 



Dr. John IV. Severingliaus: Did you measure the temperature of the dog in other 

 parts of the body? 



[)r. Keller: "^'es, but we have not done so sufficiently to give a differential tabula- 

 tion. 



Dr. JoJin U . Sei'eriiKjIiaiis: I asked alxiut temperature gradients in various por- 

 tions of the body because of a curious observation we have made. During cooling, 

 the rectal and colonic temperature of a dog falls slightly faster than the arterial and 

 esophageal temperature. However, after vagotomy, the temperature in a certain area 

 of the colon, about 15-20 cm. from the anus, uniformly falls much faster than any 

 of the other deep temperatures. We have observed temperatures 12-14 degrees 

 cooler than the arterial, esophageal, and 5 cm. rectal temperatures. This result could 

 be obtained by the use of ice water on the abdominal wall alone. However, it was 

 not due to direct heat transfer through the thin layer of wall, since the thermocouple 

 at autopsy was far from the surface. There was no measurable fall in portal flow 

 with vagotomy, so we do not believe this fall to be due to lack of blood flow to the 

 colon. Our unproven hypothesis is that after vagotomy, blood from the abdominal 

 wall may return to the systemic circulation by way of veins closely associated with 

 this area of the colon. It may be, therefore, that other neurologic lesions might pro- 

 duce this anomaly and give erroneous temperature recordings if deep rectal tem- 

 perature alone is measured. 



Dr. Jean Calm: Did you cool thyroidectomized animals? 



Dr. Keller: No, we have not. 



Dr. Calm: We did many experiments on adrenalectomized or hypophysectonn"zed 

 rats, either in surface cooling technique or in artificial hibernation, and we observed 

 the same results. But we found that it is very difficult to cool some thyroidectomized 

 animals. They resist the cooling even more when the thyroidectomy has been done 

 for two or three days. 



It would seem the resistance against cold is greatest after three or four or five 

 days, and it is impossible to obtain the same drop in the body temperature as in the 

 control if we don't block the thyrotropic secretion* by iodine proteins (tyrosine or 

 thyroxine). If we did, we obtained a drop in the colonic temperature for thvroid- 

 ectomized animals similar to that obtained in the control. 



