136 FUNCTIONS OF THE NERVOUS SYSTEM. 



proved very slowly : it was on the 53d day that he first slightly perceived the 

 heat of the metal plate. 



179. This important case suggests many interesting reflections. Common 

 sensation was not so completely abolished as in the former instance ; but of 

 the peculiar kind of impression, which was found most efficacious in exciting 

 reflex movements, no consciousness whatever was experienced. Not less 

 interesting was the circumstance, that convulsions could be readily excited by 

 impressions on surfaces above the seat of injury ; as, by pulling the hair of 

 the scalp, a sudden noise, and so on. This proves two important points : first, 

 that a lesion of the cord may be such as to intercept the transmission of volun- 

 tary influence, and yet may allow the transmission of that reflected from inci- 

 dent nerves. Secondly, that all influences from impressions on incident 

 nerves are diffused through the cord ; for, in the instance adduced, the reflect- 

 ed influence was undoubtedly not made to deviate into the cord by the morbid 

 condition of that organ, but followed its natural course of diffusion, being ren- 

 dered manifest in this case by the convulsions which were excited, in conse- 

 quence of increased activity of the motor function of the cord. It is further 

 interesting to remark, that in the foregoing case, the reflex actions were very 

 feeble during the first seven days, in comparison with their subsequent en- 

 ergy, being limited to slight movements of the feet, which could not always 

 be excited by tickling the soles. In another case of very similar character, it 

 was three days after the accident, before any reflex actions could be produced. 

 It is evident, then, that the spinal cord must have been in a state of concus- 

 sion, which prevented the manifestation of its peculiar functions, so long as this 

 effect lasted ; and it is easy, therefore, to perceive that a still more severe 

 shock might permanently destroy its power, so as to prevent the exhibition of 

 any of the phenomena of reflex action. 



180. It seems well established, then, by such cases, that the Spinal Cord, 

 or small segments of it, may serve in Man as the centre of very energetic 

 reflex actions, when the voluntary power exercised through the Brain, over 

 the muscular system, is suspended^ or destroyed. And it is further evident, 

 that these movements are produced by a mere physical change in the nervous 

 centres; the consciousness of the individual not being affected in their per- 

 formance, and sensation having, therefore, no necessary participation in them. 

 As the movements witnessed in the lower animals, under the same circum- 

 stances, are altogether of a similar character, there seems no good reason to 

 attribute to their Spinal Cord an attribute, of which it is certainly destitute in 

 Man. There is no essential difference, either in structure, or in the nature 

 of the actions performed by them, between the Spinal Cord and the Medulla 

 Oblongata, which can warrant us in assigning to the latter a function that the 

 former does not possess : and if the reflexions of the Spinal Cord do not involve 

 sensation, there is good reason for concluding, that this change is not a neces- 

 sary element in those of the Medulla Oblongata. It is perfectly true, that it 

 usually accompanies in us the greater number of actions, to which that division 

 of the centre is subservient ; for example, those of respiration and degluti- 

 tion : and it is scarcely possible for such an accident to occur in the Human 

 being, as the separation of the Medulla Oblongata from the brain, without the 

 destruction of the independent functions of both. It is not likely that we can 

 ever have the power of ascertaining, by the testimony of a patient so affected, 

 that the respiratory movements are performed without the necessary interven- 

 tion of sensation; as we have been able to do in regard to other reflex move- 

 ments. But as the general fact is, that there is no positive ground whatever 

 for regarding any part of the spinal cord as a sensorlum independent of the 

 brain, and that the respiratory movements certainly correspond in all their 

 conditions with the actions denominated reflex,there would seem no good 



