702 FUNCTIONS OF THE CEREBRO -SPINAL NERVOUS SYSTEM. 



associated with the destruction of that part of the brain which is the centre 

 for the movements of articulation. As regards sensory localization, Ferrier 

 has recently concluded a series of experiments on monkeys in which he 

 claims to have localized the regions of special sense. These regions he re- 

 gards as the centres of sensory perception as distinct from the centres of 

 sensory impressions or sensori-motor action. The following is an abstract of 

 these later researches, in which also attempts have been made to ascertain 

 the functions of those parts of the hemispheres which do not react to stim- 

 ulation: 1 1. Ablation of the frontal regions which give no reaction to 

 electrical stimulation is without effect on the powers of sensation or volun- 

 tary motion, but causes marked impairment of intelligence, and of the 

 faculty of attentive observation. 2. Destruction of the gray matter of the 

 convolution dividing the fissure of Rolando, causes paralysis of voluntary 

 motion on the opposite side of the body ; while lesion circumscribed to special 

 areas in these convolutions, previously localized by the author, causes paraly- 

 sis of voluntary motion, limited to the muscular action excited by electrical 

 stimulation of the same parts. 3. Destruction of the angular gyrus (pli 

 courbe) causes blindness of the opposite eye, the other senses and voluntary 

 motion remaining unaffected. This blindness is only of temporary duration, 

 provided the angular gyrus of the other hemisphere remain intact; when 

 both are destroyed, the loss of visual perception is total and permanent. 4. 

 The effects of electrical irritation and the results of destruction of the supe- 

 rior temporo-sphenoidal convolution indicate that they are the centres of the 

 sense of hearing. 5. Destruction of the hippocampus major and hippocam- 

 pal convolution abolishes the sense of touch on the opposite side of the body. 

 6. The sense of smell (for each nostril) has its centre in the gubernaculum 

 coruu Ammouis or tip of the unciuate convolution on the same side. 7. 

 The sense of taste is localized in a region in close proximity to the sense of 

 smell, and is abolished by destructive lesion of the lower part of the temporo- 

 spheuoidal lobe. (The action is crossed.) 8. Destruction of the optic thal- 

 amus causes complete anaesthesia of the opposite side of the body. 9. 

 Ablation of the occipital lobes produces no effect on the special senses or in 

 the powers of voluntary motion, but is followed by a state of depression and 

 refusal of food not to be accounted for by mere constitutional disturbance 

 consequent on the operation. The function of these lobes is regarded as still 

 obscure, but considered as in some measure related to the systemic sensation. 

 Their destruction does not abolish the sexual appetite. 10. After removal 

 both of the frontal and occipital lobes an animal still retains its faculties of 

 special sense and the power of voluntary motion. In the experiments made 

 by the committee of the New York Society of Neurology and Electrology, 

 including Drs. Daltou, Arnold, Beard, Flint, and Mason, 2 results confirma- 

 tory of Hitzig's observations were met with. They found that all the centres 

 of motion for the anterior and posterior limbs are situated in the convolution 

 immediately surrounding the frontal fissure which runs transversely to the 

 longitudinal fissure. The centres for flexion and extension of the anterior 

 and posterior limbs were always found in the external part of the pr;e- 

 f rental convolution just anterior to this fissure, and in the post- frontal con- 

 volution just behind it. In a majority of cases those for the anterior limbs 

 were situated more in front, near the outer extremity of the frontal fissure, 

 and those for the posterior limbs more posteriorly and inwards, but their 

 exact positions varied somewhat in different cases. The centre for flexion of 

 the head and neck in the median line is in the lateral and anterior part of 



1 Experiments on the Brain of Monkeys, second series, read before the Royal 

 Society, May loth, 1875. Abstract of Croonian Lecture. 



2 Reported in Nesv York Med. Journ., March, 1875. 





