FUNCTIONS OF THE CEREBRUM. 337 



we do not assume that anatomical and functional regenera- 

 tion of the cerebrum in a pigeon is impossible, it must be 

 admitted that such an extraordinary statement as that made 

 by Yoit cannot be accepted without reserve, upon the basis 

 of a single observation. 1 



Pathological Facts bearing upon the Functions of the 

 Cerebrum. A careful study of the phenomena which attend 

 certain pathological conditions of the brain in the human 

 subject, such as laceration or pressure from effusion of blood, 

 softening of the nervous substance, etc., taken in connection 

 with the results _of experiments upon living animals, throws 

 considerable light upon the functions of certain distinct por- 

 tions of the encephalon. Cerebral haemorrhage very common- 

 ly involves the corpus striatum, either directly or indirectly, 

 and then we have paralysis of motion limited to the side of 

 the body opposite to the lesion. When the optic thalamus is 

 affected, there is impairment of sensibility upon the opposite 

 half of the body. These facts illustrate the course of the 

 motor and sensory conductors from and to the cerebrum. 

 It is not very common to observe lesions confined to the 

 gray or white substance of the hemispheres, but when this 

 occurs, and when there is no pressure upon the corpora 

 striata or optic thalami, there is no paralysis of motion or 

 sensation, though there may be a certain amount of weak- 

 ness of the muscles upon the side of the body opposite to 

 the injury. Experiments upon the inferior animals have 



ROSEXTHAL, Sur les mouvements qui ont lieu apres Fablation des hemispheres 

 cerebraux ; Sur un pigeon auquel le professeur Volt avail enleve les hemispheres 

 cerebraux dans le mcis de juillet 1861 ; YOIT, Observations sur Fablation des 

 hemispheres cerebraux chcz le pigeon. .Archives de physiologic, Paris, 1869, tome 

 ii., p. 301. 



1 YOIT, Phenomenes qui suivent Fablafion des hemispheres du cerveau chez les 

 pigeons. Revue des cours scientifiques, Paris, 1868-1869, tome vi., p. 256. 



This observation has already been detailed in full, in connection with the 

 question of the possible regeneration of the nerve-centres after extirpation, 

 (See page 63.) 



