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PHYSIOLOGY OF THE NERVOUS SYSTEM. 



have occurred in which sensibility 1ms been 

 impaired or destroyed, while the posterior co- 

 lumns remained perfectly heulthy. In a re- 

 markable case related by Dr. Webster, there 

 was complete paralysis of motion in the lower 

 extremities, but sensibility remained; yet there 

 was total destruction of the posterior columns 

 in the lower pai't of the cervical region. Dr. 

 Webster did me the favour to allow me to 

 examine the spinal cord in this case, and I was 

 struck with the complete solution of continuity 

 of the posterior columns in the region of the 

 neck : it was impossible in this case that the 

 nervous force could have travelled along the 

 course of these columns, whether from above 

 downwards, or from below upwards. Such a 

 case as this shows distinctly that sensation may 

 be enjoyed in the inferior extremities indepen- 

 dently of the posterior columns, and if it does 

 not prove that these columns are not the ordi- 

 nary channels through which sensitive impres- 

 sions are conveyed to the brain from parts sup- 

 plied by spinal nerves, it at least shows that 

 there must be some other channel besides them 

 for the transmission of sensitive impressions. 



Other cases to the same purport are on re- 

 cord. Mr. Stanley published an account of a 

 case of this kind in the twenty-third volume of 

 the Medico-Chirurgical Transactions. He 

 states, " there was no discoverable impairment 

 of sensation in any part of either limb: on 

 scratching, pricking, and pinching the skin, 

 nowhere was any defect of feeling acknow- 

 ledged by the patient. In the upper limbs 

 there existed no defect, either of motion or 

 sensation." There was inability to expel the 

 urine or retain the faces. The report of the 

 post-mortem appearances in this case is not 

 quite so exact as might be desired. The pos- 

 terior half of the cord and the posterior co- 

 lumns are spoken of as if synonymous ; now 

 it is evident that the posterior half of the cord 

 consists of a great deal more than the posterior 

 columns; it includes the posterior part of the 

 antero-lateral columns. The record of the case 

 states as follows: "The substance of the cord 

 throughout its posterior half or column, and 

 in its entire length, from the pons to its lower 

 end, had undergone the following changes of 

 colour and consistence ; it was of a dark brown 

 colour, extremely soft and tenacious. The 

 substance of the cord through its anterior half 

 and entire length exhibited its natural whiteness 

 and firm consistence ; and on making a longi- 

 tudinal section of the cord through its centre, 

 and in the anteroposterior direction, the boun- 

 dary line between the healthy and diseased 

 nervous matter was seen to be most exact: it 

 was a straight and uninterrupted line from the 

 pons to the lower end of the cord. The roots 

 of the spinal nerves were unaltered." 



Supposing that the posterior columns are the 

 media of sensation to parts supplied by spinal 

 nerves, we can by no means infer that the 

 lesion in this case recorded by Mr. Stanley was 

 sufficient to destroy sensation ; it cannot, how- 

 ever, be conceded that, if this view were 

 correct, such a lesion could exist without im- 

 pairing sensation in some way or other, inas- 



much as the whole of the posterior columns 

 were involved in a notably diseased condition. 



The following case is related by Cruveilhier. 

 A young amaurotic girl, paraplegic of move- 

 ment only, died from some unknown cause. 

 The spinal cord presented on its posterior sur- 

 face in its entire length a large reddish-grey 

 (gris-rose) column, formed by the posterior 

 columns. All the rest of the cord was per- 

 fectly healthy. 



In a case recorded by Dr. Wm. Budd it is 

 stated that the lower extremities were quite 

 deprived of motion, " but with sensation un- 

 affected." The disease was the result of a 

 severe blow on the back from the boom of a 

 ship, which led to a curvature of the spine, 

 formed by prominence of the dorsal vertebras 

 from the fourth to the ninth inclusive. After 

 death a portion of the cord, about two inches 

 in length, corresponding to the curvature, was 

 found softened in the posterior columns. The 

 tissue was not diffluent, but became flaky and 

 partially dissolved when a small and gentle 

 current of water was poured on it. In this 

 case, no more than in that of Mr. Stanley, the 

 lesion was not enough to destroy sensation, but 

 surely it was sufficient to impair it, if the 

 posterior columns are to be regarded as the 

 channels of sensation.* 



Serres records the case of a woman who had 

 been paraplegic for two months: sensibility 

 was preserved in the lower extremities; the 

 lesion consisted in disease of the posterior 

 columns of the cord below the middle of the 

 dorsal region.f 



In two cases which occurred in King's Col- 

 lege Hospital under my own care, the promi- 

 nent symptom was impairment of the motor 

 power, without injury to the sensitive; yet the 

 seat of organic lesion in both was in the pos- 

 terior columns of the cord. 



Nasse, in the paper before referred to, alludes 

 to several cases of the same nature, in which 

 disease affected the posterior columns, but did 

 not impair sensation. 



Longet, who is a warm advocate for the 

 identity of function between the posterior roots 

 and posterior columns, cites some instances in 

 which total loss of sensibility coexisted with 

 degeneration of the posterior columns as the 

 only lesion : in these cases, however, the pos- 

 terior roots of the nerves were involved in the 

 disease, and their function became impaired or 

 destroyed in consequence. A case of this 

 kind, to be conclusive upon the point in ques- 

 tion, ought to exhibit complete destruction of 

 the posterior columns, or of a considerable 

 portion of them, with perfect integrity of the 

 posterior roots and of the antero-lateral co- 

 lumns. If in such a case there were total loss 

 of sensibility in the parts in nervous communi- 

 cation with the diseased portion of the spinal 

 cord, then, indeed, we would be justified in 

 affirming that the antero-lateral columns took 

 no part in propagating sensitive impressions, 

 and that the loss of sensibility was due to the 

 morbid state of the posterior columns. 



* Mcd.-Chirurg. Trans., vol. xsii. 



t Anat. Comp. <iu Cerveau, vol. ii., p. 221. 



