THE CORTICAL THERMIC CENTER. 



can be awakened from sleep by loud shouting, but it hears much like a hu- 

 man being who has just been aroused from deep sleep by being called, without 

 at once comprehending the call with clear consciousness. The disturbance of 

 the other senses is analogous in character. The animal howls when hungry, 

 then eats until its stomach is entirely filled. It is absolutely indifferent and 

 without sexual instinct. 



With reference to the localization in the cerebrum Goltz holds dissenting 

 views. He believes that every portion of the cerebrum takes part in the func- 

 tions upon which volition, sensation, imagination, and thought are based. Every 

 portion, independently of the others, is connected by conducting paths with all 

 of the voluntary muscles, and on the other hand, with all of the sensory nerves of 

 the body. 



After removal of an anterior lobe, including the motor zone, there develop 

 first unilateral motor and sensory paralysis and unilateral visual disturbance. 

 Of these only the loss of muscle-sense is left after the lapse of months. Removal 

 of the anterior lobe on both sides gives rise to these phenomena in more marked 

 degree, and in addition there occur innumerable involuntary associated move- 

 ments and increased reflex irritability. Goltz observed repeatedly general hyper- 

 esthesia, a remarkable motor propensity and an irritable aggressive character in 

 the dog. Marked permanent disorders in the utilization of the senses of sight, 

 hearing, smell, and taste are not necessarily present, even in connection with pro- 

 found and extensive destruction of the forebrain. 



Removal of the occipital lobes disturbs the utilization of the sense-perceptions 

 in consequence of the defect of intelligence present. The sense of sight is injured 

 most. Removal of the occipital lobe on both sides causes marked disturbance 

 of vision, but not total blindness. In character the dogs become good-natured 

 and considerate. There are never disorders of movement and of the muscular 

 sense. 



According to Loeb, a pupil of Goltz, the disorders of vision, of sensibility, 

 and of motility that develop after partial injury of the cortex can be summarized 

 as follows: On the opposite side stimulation of the retina and the sensory nerves 

 causes less marked effects that appear more slowly. Likewise the stimulation 

 of the muscles in connection with intended movements of the body is less marked 

 upon the opposite side of the body. 



Injuries of the cerebrum give rise also to inhibitory phenomena, including 

 motor disturbances; and Goltz considers the complete hemiplegia that is 

 not rarely observed after coarse unilateral injuries of the cortex as an inhibitory 

 phenomenon. The injury exerts an inhibitomotor influence upon other (infra- 

 cortical) organs, which resume their movement as soon as the inhibitory influence 

 is removed. 



Other Cerebral Functions. Some investigators have observed variations in 

 blood-pressure and change in the heart-beat after irritation of the cerebral cortex ; 

 thus, for example, Bochefontaine after electrical irritation of the motor area for 

 the extremities. After irritation of the cortical center for the facial nerve (Fig. 

 258, 5) R. Danilewsky observed increase in the blood-pressure, the pulse being at 

 first accelerated and later slowed (and also upon irritation of the caudate nucleus 

 and the adjacent white matter). At the same time, he observed, under 

 such conditions, slowing and at times interruption of the respiration. Balogh 

 observed acceleration of the pulse after irritation of various portions of the cortex 

 in the dog and slowing of the pulse after irritation of one point. Eckhard irri- 

 tated the surface of the cerebrum in rabbits and found, as a rule, that so long as 

 only a few contralateral movements take place in the anterior extremities, no 

 influence upon the heart is observed, but that cardiac symptoms appear only in 

 association with the occurrence of other movements. They consist in slower, 

 stronger pulse-beats, intermixed with feebler beats, together with slight increase 

 in the blood -pressure. If the vagus on each side be first divided the influence 

 upon the pulse-beat is not exhibited, but the elevation of the blood -pressure 

 persists. All of these experiments fail to afford a satisfactory explanation of 

 the relations of the cerebrum to the action of the heart. That such a relation 

 exists is indicated indubitably by the effect of psychic influences upon the heart- 

 beat, as Homer and Chrysippus knew. 



Irritation of the cortex laterally from the base of the olfactory tract exerts 

 a slowing or inhibitory influence upon respiration, while irritation in the 

 motor regions has an accelerating influence, and irritation of the uncinate gyrus 

 causes sniffing. Unverricht observed arrest of respiration in the dog on irritation 



