288 FUNCTIONS OF THE NERVOUS SYSTEM. 



in interrupted jets, and the passage of the faeces 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 cir- 

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

 any effort of the will, to control or moderate them." The patient subse- 

 quently regained, in a gradual manner, both the sensibility of the lower ex- 

 tremities, and voluntary power over them ; and as voluntary power increased, 

 the susceptibility to involuntary movements, and the extent and power of these, 

 diminished. 



367. 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 ex- 

 periments 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, with- 

 out the creature moving, or giving any expression of suffering, if the spinal 

 cord had been divided : yet that, by irritation of the foot, especially by heat, 

 in an animal similarly circumstanced, violent convulsive actions in the leg and 

 tail were excited. It should be added that, in the foregoing case, the nutrition 

 of the lower extremities was not impaired, as in most cases of paraplegia. 

 The rationale of this phenomenon, which is to be constantly observed when 

 the reflex actions of the part remain entire, will be hereafter noticed (Chap. 

 VII.). 



368. In another case, the paralysis was more extensive, having been pro- 

 duced by an injury (resulting from a fall into the hold of a vessel) at the lower 

 part of the neck. There was at first total loss of voluntary power over the 

 lower extremities, trunk, and hands ; slight remaining voluntary power in the 

 wrists, rather more in the elbows, and still more in the shoulders. The 

 intercostal muscles did not participate in the movements of respiration. The 

 sensibility of the hands and feet was greatly impaired. There were retention 

 of urine, and involuntary evacuation of the faeces. Recovery took place very 

 gradually; and during its progress, several remarkable phenomena of reflex 

 action were observed. At first, tickling one sole excited to movement that 

 limb only which was acted upon ; afterwards, tickling either sole excited both 

 legs, and, on the 26th day, not only the lower extremities, but the trunk and 

 other extremities also. Irritating the soles, by tickling or otherwise, was at 

 first the only method, and always the most efficient one, by which convulsions 

 could be excited. From the 26th to the 69th day, involuntary movements in 

 all the palsied parts continued powerful and extensive, and were excited by 

 the following causes: In the lower extremities only, by the passage of flatus 

 from the bowels, or by the contact of a cold urinal with the penis; convulsions 

 in the upper extremities and trunk, attended with sighing, by plucking the 

 hair of the pubes. On the 41st day, a hot plate of metal was applied to the 

 soles, and found a more powerful excitor of movement than any before tried. 

 The movements continued as long as the hot plate was kept applied; but the 

 same plate, at the common temperature, excited no movements after the first 

 contact. The contact was distinctly felt by the patient; but no sensation of 



