FUNCTIONS OF THE SPINAL CORD. REFLEX ACTION. 287 



phalous human infants (in which all the ordinary reflex actions have been ex- 

 hibited, with an entire absence of brain), without supposing that the Medulla 

 Oblonguta is the seat of a sensibility which we know that the lower part of 

 the Spinal Cord does not possess ; and of this there is no evidence whatever. 



365. Experiments on the lower animals, then, and observation of the phe- 

 nomena manifested by apoplectic patients and anencephalous infants, might 

 lead to the conclusion, that the Spinal Cord does not possess a sensibility, 

 and that its reflex actions are independent of sensation. At this conclusion, 

 Prochaska, Sir G. Blane, Flourens, and other physiologists, had arrived ; but 

 it was not until special attention was directed to the subject by Dr. M. Hall, 

 that facts were obtained by which a positive statement of it could be supported. 

 For the question might have been continually asked, If the spinal cord in 

 Man is precisely analogous in function to that of the lower Vertebrata, why 

 are not its reflex phenomena manifested, when a portion of it is severed from 

 the rest by disease or injury ? The answer to this question is twofold. In 

 the first place, simple division of the cord with a sharp instrument leaves the 

 separated portion in a state of much more complete integrity, and therefore 

 in a state much more fit for the performance of its peculiar functions, than it 

 ordinarily is after disease or violent injury ; and as the former method of di- 

 vision is one with which the Physiologist is not likely to meet in Man as a 

 result of accident, and which he cannot experimentally put in practice, the 

 cases in which reflex actions are manifested, are likely to be comparatively few. 

 But, secondly, anumberof such instances have now been accumulated, sufficient 

 to prove that the occurrence is by no means so rare as might have been sup- 

 posed ; and that nothing is required but patient observation, to throw great 

 light on this interesting question, from the phenomena of disease. A most 

 valuable collection of such cases, occurring within his own experience, has 

 been published by Dr. W. Budd ;* and the leading facts observed by him will 

 be now enumerated. 



366. In the first case, paraplegia was the result of angular distortion of the 

 spine in the dorsal region. The sensibility of the lower extremities was ex- 

 tremely feeble, and the power of voluntary motion was almost entirely lost. 

 " When, however, any part of skin is pinched or pricked, the limb that is 

 thus acted on jumps with great vivacity; the toes are retracted towards the 

 instep, the foot is raised on the heel, and the knee so flexed as to raise it off 

 the bed ; the limb is maintained in this state of tension for several seconds 

 after the withdrawal of the stimulus, and then becomes suddenly relaxed." 

 " In general, while one leg was convulsed, its fellow remained quiet, unless 

 stimulus was applied to both at once." "In these instances, the pricking and 

 pinching were perceived by the patient; but much more violent contractions 

 are excited by a stimulus, of whose presence he is unconscious. When a 

 feather is passed lightly over the skin, in the hollow of the instep, as if to 

 tickle, convulsions occur in the corresponding limb, much more vigorous than 

 those induced by pinching or pricking; they succeed one another in a rapid 

 series of jerks, which are repeated as long as the stimulus is maintained." 

 "When any part of the limb is irritated in the same way, the convulsions 

 which ensue are very feeble, and much less powerful than those induced by 

 pricking or pinching." " Convulsions, identical with those already described, 

 are at all times excited by the acts of defecation and micturition. At these 

 times, the convulsions are much more vigorous than under any other circum- 

 stances, insomuch that the patient has been obliged to resort to mechanical 

 means to secure his person while engaged in these acts. During the act of 

 expulsion, the convulsions succeed one another rapidly, the urine is discharged 



* Medico-Chirurgical Transactions, vol. xxii. 



