Ixx Journal of Comparative Neurology. 



and that permanently. In the animals experimented upon — monkeys 

 — the movement of grasping never occurs either with hand or foot. 

 The affected limb hangs passively flexed. Associated movements of 

 the limb are comparatively little impaired, while the independent and 

 more delicately adjusted movements which employ preponderantly 

 the smaller and more individualized muscular masses of the hand and 

 foot, and serve to move the digits, especially the hallux and the thumb 

 — in fact, just those movements which are represented most liberally in 

 the limb area of the cortex — are extremely severely impaired, and, in 

 some instances, are abolished. Several weeks after the operation elec- 

 trical stimulation of these areas and convulsions induced by absinthe 

 epilepsy both gave reactions which were little if at all different from 

 those of the uninjured hmbs. These observations seem to the author 

 to point to the profound difference existing between the production of 

 the finer movements of the limb in volition on the one hand, and by 

 experimental stimulation of the cortex on the other. Their importance 

 to the theory of cortical localization is obvious. 



Upon section of a single sensory root no paralysis occurs, due to 

 the fact of overlapping of the areas of peripheral distribution so that no 

 area of anaesthesia is produced. But, even if an area of absolute anaes- 

 thesia be produced by the section of several roots, and even though 

 this area be the highly sensitive palm, yet the impairment of movement 

 resulting in the limb is comparatively slight if sensibility in an impaired 

 degree be permitted to the adjacent parts. If, however, the whole 

 hand or foot be rendered anaesthetic the impairment of movement is 

 about as great as if the entire hmb were affected ; while conversely, if 

 the whole series of sensory roots belonging to a limb be destroyed 

 except those of the hand or foot, the impairment of motion is slight. 



The experiments were applied to the study of the so-called muscu- 

 lar sensations. It is possible to sever the sensory fibres from the 

 muscles of the limb without interfering to any great extent with those 

 from the skin. In this case there is no appreciable defect of move- 

 ment ; conversely, if the sensory fibres from the skin are destroyed and 

 those from the muscles are left intact, the defect in movement is 

 extreme. 



No disturbances in nutrition were demonstrated in the areas rend- 

 ered anaesthetic. The degenerations in the cord showed that the fibres 

 of GoU's column are mainly derived from the sensory roots from the 

 lower limb, while the fibres of Burdach's column are derived largely 

 from the dorsal roots from the upper limb. On the other hand, section 

 of a short series of five dorsal and upper lumbar roots produced no ap- 



