22 F. T. ROGERS 



types, such as to suggest damage to the cerebellum or to the 

 labyrinthine mechanisms. 



5. Body temperature may become subnormal. (The normal 

 in the pigeon is from 39° to 42°C). 



6. Immediately after operation forced continuous walking or 

 flying independently of the conditions of the digestive tract. 

 These I have seen only during the first day or two after operation. 



As recognized by Vulpian and Munk: 



7. No characteristic periodic restlessness associated with 

 hunger. 



8. Loss of all instincts, as in the bird deprived of hemispheres 

 only. 



As a matter of fact, if the thalamus be removed, such animals 

 usually die unless, 1) particular care has been taken that the 

 operation is properly done, and, 2) great care is taken after oper- 

 ating to keep the animal warm and furnish some food and water 

 by forced feeding if necessary. Furthermore, the picture of such 

 animals after operation is quite variable, including all kinds of 

 mixtures of the points just outlined as characteristic of thalamic 

 injury. Examples of such behavior are as follows: 



Pigeon 104 



November 10. Decerebration and thalamus cauterized. 



November 11. Bird walking about. 



November 12. Temperature subnormal; feathers flat; bird sluggish; 

 bird stands with difficulty with outspread feet. 



November 13. Feathers slightly fluffed; bird stands quietly; pupils 

 dilated; temperature subnormal. 



November 15. Bird rejects food put in mouth; pupils constricted; 

 reflexes sluggish. 



November 16. Bird quiet; no movement. Given feed and water. 



November 22. Bird stands on its feet unsteadily; pupils normal; 

 temperature normal; reflexes sluggish. 



November 23. Bird dead with crop and gizzard filled with food. 



Pigeon 105 



November 8. Decerebration and thalamus cauterized. 

 November 9. Temperature subnormal; pupils dilated; swallows water 

 easily; bird sits on floor of cage. 



