RECENT NEUROLOGICAL PROGRESS. 283 



ment in a limb it must be remembered that defect is easier 

 found in the fine apical parts than in the larger, coarser 

 proximal. When Dr. Grace, the cricketer, drives two suc- 

 cessive balls to the off, an inch less or more in the lunoe 

 forward of the shoulder is probably imperceptible to veteran 

 players in the field, but the variation by a small fraction of 

 an inch in the turn of the wrist is obvious at once to the 

 least practised onlooker ; the ball in consequence takes dif- 

 ferent direction between the surrounding fielders. The 

 impairment of movement so obvious at the distal joints of 

 the limb may exist at proximal also but be undetected. It 

 is precision of movement of limb rather than apical move- 

 ment of limb that suffers. Because in the motion of apical 

 parts of the limb the role played by precision is greater 

 than in proximal, apical movement appears so much in- 

 jured. 



In result of lesion of the gefuhl-sph'are one derangement 

 — a corollary naturally consequent in the view held by Munk 

 — is very clearly exhibited by the interesting records recently 

 published by Mott. 1 Mott notes that the impairment of 

 cutaneous sensation is greater at the apex of the limb than 

 in the proximal part of it. Were the muscular sense 

 examined in suitable patients carefully as for normal persons 

 by Goldscheider and Waller, it would probably reveal 

 increasing deficit in a centrifugal direction along the serial 

 portions of the limb. To make further comparison between 

 limb cortex and visual cortex one might say that the apex 

 of the limb in the former is the analogue of fovea centralis in 

 the latter. Just as in the former the reactions of the digits 

 predominate, so in the latter the reactions belonging to the 

 fovea. The cortical projection of the thumb, as of the fovea, 

 is relatively large. By such comparison becomes clearer the 

 peculiar importance of the cerebral cortex for the "high 

 level " movements, which find expression chiefly through 

 the instruments of precision, the apical members of the limb. 

 It is the reactions of these members which will suffer in the 

 limb as in the retina the reactions of the region of central 



1 Journal of Physiology, January, 1894, p. 464. 



