594 



ouly a thiu layer of fibres seems to be employed in the transmission 

 of sensitive impressions, this layer forming the surface of these 

 columns which is in contact with the gray matter. 



IV. After having ascertained that there are some nerve-fibres in 

 the white anterior columns which are employed in the transmission 

 of sensitive impressions, I have tried to find if these fibres are sen- 

 sitive or not, that is, able to give pain as the posterior roots of nerves, 

 or unable to give pain, as the gray matter ; and have found that they 

 seem to be totally deprived of sensibility. 



HI. " Summary of a paper (to be presented) on the resemblance 

 between the effects of the section of the Sympathetic Nerve 

 in the Neck and of a transverse section of a lateral half of 

 the Spinal Cord." By E. BROWN-SEQUARD, M.D. Com- 

 municated by JAMES PAGET, Esq., F.R.S. Received 

 June 25, 1857. 



I will merely indicate here the principal points of similitude be- 

 tween the effects of these two experiments. Some of the results here 

 mentioned as observed after the section of the sympathetic nerve in 

 the neck, have been discovered by Prof. Bernard ; the others have 

 been found by myself. As to the effects of the section of a lateral 

 half of the spinal-cord, I have discovered all of them. 



Section qf the cervical sympathetic 

 nerve; its effects on the corre- 

 sponding side of the face. 



1. Blood-vessels dilated (paralysed). 



2. As a consequence, more blood. 



3. Elevation of temperature. 



4. Sensibility slightly increased. 



5. Ditto lasting longer there than on 



the other side, when the animal 

 is chloroformized. 



6. Sensibility lasting longer there than 



on the other side during agony. 



7. Many muscles contracted. 



Section of a lateral half of the spinal 

 cord in the dorsal region; its 

 effects on the posterior limb, on the 

 corresponding side. 



1. The same effect. 



2. Ditto, ditto. 



3. Ditto, ditto. 



4. Very much increased. 



5. Lasting longer than anywhere else 



during chloroformization. 



6. Lasting longer than anywhere else 



during agony. 



7. A state of slight contraction in many 



muscles. 



