312 PHYSIOLOGY CHAP. 



inhibits the activities, not merely of the parts directly injured, 

 but also of the more remote parts which have not received direct 

 injury. Even when contusion or traction is as far as possible 

 avoided, a transection can suspend all activity in the cord for a 

 certain time. 



Marshall Hall first gave the name of " shock " to this temporary 

 depression or total inhibition of the nervous functions after 

 mechanical injury to any part of the system. Goltz held the 

 phenomena of shock to be due exclusively to inhibition, but this 

 is doubtful. If the mechanical lesion is regarded as a powerful 

 stimulus, then shock may be conceived as exhaustion of excitability 

 in the elements involved. As by transection of the cord the 

 lower part is suddenly severed from the higher centres, we may 

 hold with Foster that the phenomena of shock which it exhibits 

 may arise partly from the withdrawal of the stream of influences 

 which reached it while still connected with the rest of the system, 

 and that these phenomena subsequently disappear as the cord 

 becomes adapted to the new conditions and learns to function 

 independently. 



Amongst " laboratory animals," monkeys exhibit spinal shock 

 at its maximum after transection of the cord (Sherrington). The 

 fact should be noted that the shock appears to take effect in the 

 aboral direction only. After high cervical transection, the effects 

 of shock are more severe in the fore-limbs than in the hind ; for 

 an hour or so it may be difficult to elicit a reflex by any kind and 

 any strength of stimulus. 



In the dog this functional depression usually wears off in about 

 five weeks after a brachial transectiou. In man transection of 

 the cord profoundly disturbs the functions of the skeletal muscles, 

 and to a certain extent those of the viscera, as in monkeys. 



G-oltz assumed that the phenomena of shock may persist for 

 months in the isolated part of the cord. Sherrington, on the 

 other hand, inclines to think that the true shock phenomena 

 pass off much more rapidly, and are succeeded by permanent 

 functional alterations, which in many ways resemble a recrudescence 

 of shock. These are probably caused by " isolation-dystrophy " 

 due to the withdrawal from the spinal nerve-cells of the influences 

 they are accustomed to receive from higher parts of the nervous 

 system. In any case, it is certain that the phenomena of functional 

 depression due to transection of the cord are more pronounced and 

 permanent in man and in the ape than in the dog and rabbit, 

 while they are quite transitory in the frog and other cold-blooded 

 vertebrates. The increasing gravity of shock in ascending the 

 vertebrate scale is probably due to the increasing influence of the 

 great projection system of the brain on the motor organ in the 

 higher animals. The relative insignificance of shock in the 

 visceral system, and slight differences in the animal scale in this 



