OTHER FUNCTIONS OF THE SPINAL CORD. 157 



already quoted, ( 177, 8,) when the control of the will over the lower extre- 

 mities was lost, powerful muscular actions were excited in them through the 

 Spinal Cord alone. In the healthy condition of the Human system, when the 

 Will is controlling all the movements which are not immediately concerned in 

 the maintenance and regulation of the organic functions, no such actions can 

 be excited ; but, in proportion as its control is lost, does the independent power 

 of the Spinal Cord manifest itself. The more such actions are of a simple 

 rhythmical character, similar to those of Respiration, the more does it seem 

 that they may with probability be referred to the Spinal system ; and if we 

 attribute to this (as we can scarcely help doing) the rapid vibration of the 

 wings of Insects, there seems no reason why we should not extend the same 

 view to the wings of Birds. Such an explanation of their movements will 

 account for their occasional continuance, without apparent fatigue, during a 

 period through which no known voluntary effort can endure ; for it is one of 

 the attributes of the Spinal system of nerves, well pointed out by Dr. M. Hall, 

 that the exercise of the muscles excited by it does not occasion fatigue, the 

 sense of which is Cerebral only. It would seem to the Author more probable, 

 however, that those movements which guide the body, and which must them- 

 selves be directed by Sensation, are to be referred to a class intermediate 

 between the Voluntary and the Reflex, which may be properly termed Instinc- 

 tive. Several actions in Man, which were at first Voluntary, appear at last to 

 be performed as instinctively, or intuitively, as they are in the lower animals 

 from the commencement of their existence. (See Section xvm. of the present 

 Chapter.) 



211. It would not be right to conclude this account of the principal functions 

 .of the Spinal Cord, without adverting to some of the leading Pathological 

 applications of the physiological doctrines, which have been developed in it. 

 A large part of these were first pointed out by Dr. M. Hall ;* and they are 

 receiving continual and important extensions from his own labours and those 

 of other practical inquirers. It may be remarked, in the first place, that the 

 power of the whole Spinal system is capable of being morbidly diminished or 

 augmented. It may even be for a time almost completely suspended, as in 

 Syncope ; which state maybe induced by sudden and violent impressions, either 

 of a mental or physical nature, that operate upon the whole nervous system at 

 once, commencing, however, in the Brain. It is to be remarked that, in 

 recovering from these, it is the Spinal system of which the activity is first 

 renewed, the respiratory movements recommencing, and the power of swal- 

 lowing being restored, before any voluntary actions can be performed. A cor- 

 responding state may be induced in particular portions of the system, by con- 

 cussion ; as is seen in severe injuries of the Spinal Cord, which are almost 

 invariably followed for a time by the suspension of its functions. Again, the 

 power of the whole Spinal Cord may be diminished by various causes, such as 

 enfeebled circulation, pressure, &c.; and then we have torpidity of the whole 

 muscular system. If oppression exists in the brain, the functions of the Medulla 



. oblongata will be especially affected ; and if it be prolonged and sufficiently 

 severe, Asphyxia will result from the interruption of the respiratory movements 

 which it occasions. 



212. On the other hand, the excitability of the whole Cord, or of particular 

 parts of it, may be morbidly increased. This is especially seen in Tetanus, 

 Hydrophobia, and the artificial tetanus induced by Strychnine ; so that the 

 slightest external stimulus is sufficient to induce reflex actions in their most 

 terrific forms. It is interesting to remark, that, in these formidable diseases, 



* See especially his Treatise on the Diseases and Derangements of the Nervous 

 System. 



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