SURGICAL SHOCK 45 



This curare effect is not due to any action on the 

 vessels, but to the abolition of tone of the voluntary 

 muscles. This is in accord with the results of other 

 workers. 



Do we not here find a clue to our problem ? We 

 turn back to the very first sentence of Sir Watson 

 Cheyne's classical description of shock, and read, 

 " The patient who is suffering from shock is usually 

 found lying in a state of complete muscular relaxa- 

 tion." And, later, " the reflexes are very shght." 

 Loss of tone in the voluntary muscles, in the abdominal 

 wall especially, allows great dilatation of the veins, 

 and here, as Crile observed in his experimental 

 animals, the blood accumulates. Therefore the 

 blood-pressure falls and the cardiac output is reduced 

 in spite of undiminished power of the heart muscle 

 and contracted arteries. 



We must draw attention to the very significant 

 fact that although the intramuscular and abdominal 

 veins are dilated in shock, this cannot be due to 

 some universal venodilator effect, because, as anyone 

 who has had to perform intravenous transfusion 

 on these cases will bear witness, the subcutaneous 

 veins are smaller than normal. It may be objected 

 that muscular tone is reduced in various nervous 

 diseases and under anaesthetics without a marked 

 fall of blood-pressure, but it has to be remembered 

 that in the nervous affections the onset is very 

 gradual and can be compensated, and with anaesthetics 

 there is stimulation of the heart and vasomotor 

 centre to counteract the loss of tone. Under ether, 

 at any rate, the muscles may be very vigorous, as 



