Literary Notices. clxxv 



which lasts about one-sixtieth of a second and is followed by another 

 interval of ordinary darkness. 



(6). Finally, in about a fifth of a second after the extinction of 

 the external light, there occurs another transient impression of lumin- 

 osity, generally violet-colored, after which the uniformity of the dark- 

 ness remains undisturbed. 



The Tactile Areas of the Cerebral Cortex. 1 



The third paper in Professor Munk's series on the " Fiihl- 

 sphaeren " has appeared in the July fascicle of the Transactions of the 

 Berlin Academy. In the first of these papers the author adduces ex- 

 perimental evidence in substantiation of the opinion, somewhat tenta- 

 tively expressed in an earlier work, 2 that the tactile sensations of the 

 various regions of the body are localized in cortical areas coinci- 

 dent with the motor areas already established for the same re- 

 gions. He thus reconciles the contradictory experiments of those 

 who find that there results from the destruction of these areas 

 the loss of tactile sensation only without motor disturbance 

 in the parts affected (Schiff) and those who find only motor 

 paralysis without permanent sensory disturbances (Ferrier). Be- 

 sides the account of the author's own experiments, there is an ex 

 tensive controversial discussion of the results of Goltz, Ferrier and 

 others in the same field, and especially with reference to the common 

 sensations and reflexes. It is shown that after the total extirpation of 

 the cortical area for an extremity there is an influence upon the reflex 

 centre of the cord pertaining to this extremity. The reflex excitabili- 

 ty is at first greatly diminished, but soon again increases to a maxi- 

 mum which remains constant thereafter. This diminution is not due 

 to any inhibitory effect of the operation, as taught by Goltz, but mere- 

 ly to the interruption of the paths of conduction between the cortical 

 and the spinal centres, thus making necessary a re-arrangement of the 

 elements within the latter. These phenomena are called " alterations 

 of isolation." 



The second and third papers deal with the motor disturbances 



'Munk, H. Ueber die Fiihlsphaeren der Grosshirnrinde. Sitz. derk. preuss. 

 Akad. der wissenchaften zu Berlin. 

 1st. Mittheilung, July, 1892. 

 2d. Mittheilung, Oct., 1893. 

 3d. Mittheilung, July, 1894. 



2 Ueber die Functionen der Grosshirnrinde. Zweite Anjiage, Berlin. 1890. 



