x THE FOEE-BEAIN 597 



tube introduced through a small aperture in the skull ; on remov- 

 ing part of the caudate nucleus by this means they observed 

 symptoms of sensory and motor defect on the opposite side, but 

 only of short duration. They also observed a rise of the animal's 

 temperature, for several days, to 40, an effect previously noted by 

 Sachs, Ott, and Eichet. 



Sgobbo (1892) again employed Nothnagel's trochar to destroy 

 the caudate or the lenticular nucleus alone, or the motor area, or 

 the motor area and basal ganglia. But his notes of the experiments 

 leave much to be desired ; he neglected sensory changes altogether. 

 Still he noted the interesting fact that simultaneous lesions of the 

 motor zone and the corpus striatum produce paralytic symptoms 

 which are more serious and last longer than those due to lesions 

 of one of these parts only. 



Sellier and Verger (1898) succeeded in destroying small 

 portions of the basal ganglia without damaging the surrounding 

 parts, by means of bipolar electrodes covered so as to insulate 

 them except at the points. In a dog thus operated on and killed, 

 after forty-one days, they noted partial hemiplegia of the opposite 

 side, which persisted till death; tactile hemianaesthesia, which 

 diminished after the third week ; total loss of muscular sense, 

 and normal sensibility to pain. Examination of the brain revealed 

 a focus the size of a pea in the head of the caudate nucleus, 

 and spreading to the anterior segment of the internal capsule. 

 This excellent experiment demonstrates that the symptoms due 

 to lesions of the caudate nucleus are identical with those conse- 

 quent on ablation of the senso-motor zone. 



Pagano (1906) by the exciting action of injections of curare, 

 which he had already employed on the cerebellum, attempted to 

 show the special importance, in his opinion, of the caudate nucleus 

 as " the seat of physiological mechanisms which serve the ex- 

 pression of the emotions." When curare is injected into the inner 

 half of the anterior and median third of the head of the caudate 

 nucleus it excites symptoms which suggest fear ; injected into 

 the posterior third it gives rise to symptoms of anger ; lastly, when 

 it stimulates the outer part of the anterior third of this nucleus 

 marked visceral phenomena are seen. But the injection of curare 

 by Pagano's method is manifestly inadequate for exact localisation ; 

 and the psycho-motor agitation which results gives rise to such 

 complex phenomena that any physiological analysis of them would 

 be exceedingly difficult. 



Lo Monaco's experimental extirpation of the head of the caudate 

 nucleus through the inter-hemispherical sulcus, after section of the 

 corpus callosum, represent the most exact contributions to this 

 subject (Chap. IX. p. 520). In four dogs which survived long enough 

 to allow investigation of the effects and their course, the symptoms 

 were constantly and exclusively those of motor and sensory defect 



