SPINAL SHOCK. 847 



" crossed knee-jerk." An early reaction to emerge from the spinal 

 shock is adduction-flexion of the hallux, in response to stimuli applied 

 to the third, fourth, or fifth digits (plantar surface or sides), or to the 

 skin of the sole, especially on its fibular side. The movement of the 

 hallux is then slight and often tremulous. A similar reflex is obtain- 

 able in the hand. In the cat and dog and rabbit an equivalent reaction 

 seems to be the arching of the digits, and this is not unfrequently 

 bilateral. Anal protrusion, in response to stimulation of the skin of the 

 perineum, feeble abduction of the tail on pricking it, are also reactions 

 which early emerge from the depression. The limbs at this time feel 

 limp and the muscles more flaccid than they do later. Gradually these 

 reflex movements become more vigorous, and others are added, e.g. the 

 cremasteric, and the drawing up of the limb on stimulation of the foot. 

 Extension of the limb is late to be obtained, and very rarely is obtained 

 as a primary homonymous reaction. Crossed reflexes appear, and the 

 march and duration of the individual reflexes gets more extensive. 

 The disappearance of " shock " is very variously rapid in different 

 individuals. In the same individual the progress is usually not steady ; 

 on some days reflexes are absent which had been gained, and reappear 

 only later. The extensors of the hips and knees recover later than 

 the flexors. In the spinal dog, after a brachial transection, it can 

 perhaps be said that in five weeks the depression of shock has usually 

 worn off. It is not renewed by a second transection practised behind 

 the first one. 



The cause of the " shock " cannot entirely be the fall of arterial pressure which 

 a transection anywhere in front of the second thoracic level must entail, for the 

 head does not participate in the shock, although participating in the lowered 

 blood pressure ; and when the transection is in the lower thoracic region, the 

 shock distal to the lesion is about as severe as after cervical transection. Besides, 

 section of both splanchnics does not cause shock. Neither is the " shock " 

 explicable by fall of deep temperature, for it occurs where that is absent and 

 has been almost avoided. It is noteworthy that, although in the monkey 

 among laboratory animals it appears most severe, and is certainly particularly 

 long lasting, it does not in that animal appear more severe as regards de- 

 pression of function of urinary bladder, rectum, etc., than in other laboratory 

 animals. It is especially well seen in the monkey that the motor root cell, 

 though in spinal shock profoundly inaccessible to stimuli applied via skin or 

 afferent nerve trunks, lies perfectly open to any applied via the pyramidal 

 paths ; excitation of the pyramidal tract at the top of the cord readily evokes 

 movements in the otherwise reactionless limbs. Also, excitation mechanical, 

 or by weak electric currents of the central ends of the spinal afferent roots 

 themselves readily evokes reflex movements, though far stronger stimuli fail 

 absolutely when applied to the skin and afferent nerve trunks. 



How long the phenomena of shock may persist, is a question on 

 which very different views are held. Goltz is the founder of a school 

 which works in the belief that the phenomena of shock may persist for 

 months or even years. My own experience inclines me to think 

 that the condition of a spinal cord, isolated by spinal transection, is often 

 more normal a short time after the transection than it is when long 

 periods of weeks and months have been allowed to elapse. The " shock " 

 passes off, to be succeeded, it seems to me, by permanent alterations that 

 in many ways resemble in their effects a recrudescence of shock. The 

 decreasing depression merges in the onset of an increasing " isolation- 



