Practical and pathological researches on the various forms of paralysis.

  • Edward Meryon
Date:
1864
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Licence: Public Domain Mark

Credit: Practical and pathological researches on the various forms of paralysis. Source: Wellcome Collection.

Provider: This material has been provided by UCL Library Services. The original may be consulted at UCL (University College London)

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    nervous centre, and regarded it simply as a main channel to convey the nervous currents to and from the brain; the con- ductors of sensation passing, as he thought, through the pos- terior and lateral columns—the conductors of volition through the anterior columns of the cord; and it was impossible, without the experiments which have since been made, that he could arrive at a correct notion on these important points.* But his theory immediately suggested the obvious means of tracing back to particular parts of the brain the causes of paralysis, and of many nervous diseases. It did not, however, account for those strange and mysterious sympathies by virtue of which the different parts of the body are maintained in a state of mutual dependence, and by means of which a disturbed condition of one organ produces impressions on the other, and, it may be, distant parts of the system. What, for instance, but this kind of affinity can occasion the contracted brow in severe headache, the dilated nostrils in painful affections of the chest, or the raised upper lip, stretched over the gums, in great suffering of the abdomen ? These and other far more important phenomena were interpreted by the thought- ful experiments of Dr. Marshall Hall, who first taught us that they are dependent on diffusion of excitement, not by the nerve primarily affected, which acts only as a conductor of sensation to the nervous centre, but by the nervous centre itself, on which the primary impression impinges, and from which it is reflected: that there is, in point of fact, a distinct and separate centre of nervous action in the spinal cord itself, independent of the brain. Thus a worm in the intestine sets up irritation, which, when transmitted to the spinal cord by the special con- ductors of sensation, may produce paralysis as a reflex action. This theory, second only to that of Sir Charles Bell for its * Majendie tested the truth of Sir C. Bell's theory by a series of experiments, and furthermore discovered that by irritating the anterior roots of the spinal nerves he induced pain, and that sometimes, too, local movements occurred when he irritated the posterior roots. In 1839 he observed that if the anterior roots be divided, it is the distal end only, when irritated, which produces pain : hence he concluded that it is an afferent conductor. He furthermore observed that if the posterior root be divided, the irritation of the anterior root no longer gives pain. From these facts he inferred that the nervous irritation which causes pain passes first to the peripheral branches, and tlien back again to the spinal cord ; and to this he gave the name of recurrent sensibility.
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