18 F. T. ROGERS 



Vulpian in 1866 noticed that removal of the cerebral hemi- 

 spheres of the carp led to continuous excessive activity of the fish, 

 always however avoiding obstacles in its path. 



Ferrier and Steiner found that removal of the hemispheres of 

 the shark gave the same picture as followed loss of the olfactory 

 lobes; that if the thalamus were removed, the animal lay quietly 

 on the floor of the aquarium without movement. Bethe denied 

 this, stating that loss of the thalamus did not abolish spontane- 

 ous movements. 



Steiner, Bethe, and Loeb all agreed that damage to the mid- 

 brain leads to motor disturbances, in the form of forced move- 

 ments or circus movements, if the lesion is unilateral, in the 

 direction of the intact half of the midbrain. 



Removal of the hemispheres and thalamus of the frog abolishes 

 spontaneous movements, according to Steiner; but not if the 

 thalamus is left intact (Schrader).' 



Rolando ( ; 09) studied the effects of decerebration in the pigeon. 

 His observations were confined to birds which lived a few days 

 only after operation. 



Flourens ('22) continued the work and kept the birds alive for 

 months after operation. He made no distinction between decer- 

 ebration with and without thalamic involvement. 



Longet ('47) was the first to attribute significance to sharp 

 localization of brain lesions and prepared decerebrate birds with 

 and without damage to the underlying parts. 



Munk, in 1883, revived the controversy between Flourens, who 

 maintained that the hemispheres were necessary for the vari- 

 ous senses, and Cuvier, who thought that loss of the forebrain 

 led merely to the loss of memory images. 



Schrader, in 1889, in an elaborate monograph reported results 

 on decerebrate pigeons in which the thalamus was carefully pre- 

 served. His primary interest was in the functions of the cere- 

 bral hemispheres and not much consideration was given to the 

 thalamus save to make sure that it was present. 



Vulpian had previously considered the activities of decerebrate 

 animals as due automatically to stimuli " either internal or exter- 

 nal" which incited the movements of the animals. 



