408 ANATOMY AND PHYSIOLOGY OF THE SPINAL CORD. 



seem to take place close to the roots of the nerves into 

 which they enter, as the following experiments show. 1st, 

 A part of the spinal cord was bisected longitudinally, so as 

 to separate the two lateral halves of the cord from each 

 other ; the result was, that sensibility was destroyed in the 

 parts supplied by nerves which leave the cord opposite the 

 portion operated on. 2d, The right half of the cord was cut 

 across in the dorso-lumbar, and the left half in the cervical 

 region, with the effect of inducing a paralysis of sensibility, 

 complete, or nearly so, in both hind limbs. The left half of 



the body and the left fore limb 

 were in this case morbidly sen- 

 sitive, while the right fore limb 

 was almost destitute of this 

 property. The crossing of the 

 fibres conducting these im- 

 pressions has been well illus- 

 trated by Lockhart Clarke. 



We have remarked that the 

 anterior columns are the chief 

 conductors of motor power 

 from the brain. Schiff, how- 

 ever, goes further, and ascribes 

 to t k e an t er i r columns proper 



rig. 213 (LOCKHART CLARKE).-Diagram 



showing the crossing of the sensory fibres 



in the spinal cord, r, Right side; Z, left the transmission of SUCll to the 



side; s, section in loins; *>, section in the limbg Qnl wnile ne part i cu _ 



J *- 



the lateral Columns as 



similar office 



neck ; /, fibres imparting sensation to the 

 right hind limb; f'tof, fibres imparting 



sensation to the left hind limb. 



performing a 



with regard to the muscles of the trunk. They would seem 

 also to be presided over by distinct nervous centres, so 

 that they act in a great measure independently of each 

 other. In support of this view, it may be mentioned that 

 Jiemiplegia is not, as its name would indicate, paralysis of 



