134 FUNCTIONS OF THE NERVOUS SYSTEM. 



a number of such instances have now been accumulated, sufficient to prove that 

 the occurrence is by no means so rare as might have been supposed ; and that 

 nothing is required but patient- observation, to throw great light on this inte- 

 resting 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 \vill be now enumerated. 



176. 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 with- 

 drawal 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 

 was 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' 

 other 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 circumstances, 

 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 in inter- 

 rupted jets, and the passage of the fasces suffers a like interruption." The 

 convulsions are more vigorous, the greater the accumulation of urine ; and 

 involuntary contractions occur whenever the bladder is distended, and also 

 when the desire to relieve the rectum is manifested. "In all these circum- 

 stances, the convulsions are perfectly involuntary ; and he is unable by any 

 effort of the will, to control or moderate them. The patient subsequently 

 regained, in a gradual manner, both the sensibility of the lower extremities, 

 and voluntary power over them; and as voluntary power increased, the sus- 

 ceptibility to involuntary movements, and the extent and power of these, dimi- 

 nished. 



177. This case, then, exhibits an increased tendency to perform reflex 

 actions, when the control of the brain was removed ; and it also shows that a 

 slight impression upon the surface, of which the patient was not conscious, 

 was more efficacious in exciting reflex movements than were others that more 

 powerfully affected the sensory organs. This is constantly observed in expe- 

 riments upon the lower animals ; and it harmonizes, also, with the important 

 fact, that when the trunk of an afferent nerve is pinched, pricked, or other- 

 wise irritated, the reflex function will not be nearly so strongly excited as 

 when a gentler impression is made on a surface supplied by the' branches of 

 this nerve. The former produces pain, whilst the latter does not ; the amount 

 of sensation, therefore, does not at all correspond with the intensity of reflex 

 Action, but rather bears a converse relation to it. Mr. Grainger found, that he 

 could remove the entire hind leg of a Salamander with the scissors, without 



* Medico-Chirurgical Transactions, vol. xxii. 



