28 F. T. ROGERS 



4. Birds with thalamic lesion and body temperature kept nor- 

 mal, so far as the analysis at present stands, differ from decerebrate 

 birds with thalamus intact in the following respects : 



a. A shorter period of life after operation. 



b. A tendency to stasis of food in the gastric cavities, asso- 

 ciated very frequently with vomiting. 



5. If the body temperature is allowed to fall, a gradual de- 

 pression of reflex activities ensues. 



a. In the preceding protocol it is seen that decerebrate rest- 

 lessness (walking movements) occurred with the temperature of 

 the bird at 43°, 40°, 39°, 38°, 41°. That it did not occur during 

 starvation at body temperatures of 36° and 37°, with one excep- 

 tion and that one was at 32°. The writer is inclined to think 

 that two types of restless walking movements are to be recog- 

 nized. One associated with hunger or other visceral disturb- 

 ances, and a second which is independent of reflex stimuli and is 

 automatic in the sense that it results from changes within the 

 brain tissue only. The nature of this automatic activity cannot 

 be stated now, but this type of restlessness is independent of 

 either hunger or feeding and shows itself as forced continuous 

 movements. This type of behavior is well shown in the protocol 

 of July 7. 



b. Equilibrium apparently remains normal, so far as observa- 

 tion 1 goes, until the body temperature falls to 36° or less. At 33° 

 a characteristic tonic flexion of the toes is evident which has 

 suggested the term 'claw foot.' At this temperature the animal 

 is unable to carry on the fine balancing reactions involved in 

 perching. At —20° the bird is unable to stand and lies on the 

 floorin an uncoordinated fashion with flexed toes and outspread 

 wings (fig. 2). 



c. With a decline in body temperature the nystagmus reactions 

 of the eye become more and more sluggish, disappearing alto- 

 gether at about 30°. As the body temperature falls, the rate of 

 rotation used to elicit the nystagmus must be made slower, other- 

 wise it may be overlooked and the deviation alone observed. 

 Very curiously, the compensatory movements of the head to rota- 

 tion may persist at temperatures below those at which the eye 



