284 SCIENCE PROGRESS. 



vision. Among centripetal impressions streaming in from 

 the limb, as from the retina, are many unaccompanied by- 

 parallel subjective process, and many more accompanied by 

 only dim subjective states, but over and above these the 

 cortex sits at receipt of those specific perceptions (wahrneh- 

 mungen) whence the fully elaborated "mental pictures 

 of the moment " (vorstellungen). Therefore does its 

 absence involve defect in accuracy of sensation and of 

 movement. 



In describing the impairment of the apical movements 

 of the limb Munk points out that though normally the 

 apical movements are elicitable both individually and 

 as parts of sequences, after destruction of the "limb 

 cortex " movement of a thumb or finger is no longer 

 elicitable individually, but only as part of a sequence ; 

 the sequence, he says, then runs always from proximal to 

 distal joints, i.e., a " centrifugal radial sequence," to follow 

 Mercier. 1 



Concerning restoration of function after structural injury 

 to the central nervous system, Munk, like Goltz, rejects the 

 possibility that recovery from paresis of cortical origin is 

 explicable by assumption or extension of correlative func- 

 tions seated in the cortex of the opposite hemisphere- 

 Both observers lay stress on the suppression of defects 

 under occasions of mental excitement and activity. The 

 paretic dog as feeding-time approaches becomes less paretic 

 (Goltz) ; 2 his field of vision reduced by occipital lesion be- 

 comes less so (Loeb) ; 3 " Leidenschaftlich erregt, in Angst 

 und Furcht ocler gierig nach der Nahrung, lauft der Affe 

 oder geht er rasch ; und dann werden schon zu derselben 

 Zeit, zu welcher beim gewdhnlichen langsamen Gehen, das 

 wir vorhin verfolgten, die unteren Glieder der rechten 

 Extremitaten noch passiv geschleift werden und der Affe 

 ofters umfallt, alle Glieder der rechten Extremitaten activ 

 derart bewegt, dass der Affe ohne zu stolpern oder zu fallen, 



1 The Nervous System and the Mind, London, 1888. 



2 Pfliiger's Archiv, 1883. 



8 Ibid., 1884, vol. xxxiv., p. 67. 



