24 SURGICAL SHOCK 



motor paralysis. Compare it, for instance, with 

 belladonna poisoning, in which the small arterioles 

 are undoubtedly released from nervous control, 

 causing, as we know, a flushed skin. In shock, on 

 the other hand, the skin is pale, the pulse is small, 

 bleeding is scanty, and the anuria suggests that the 

 renal vessels are contracted. The abdominal viscera 

 are pale unless they have been long exposed. Seelig 

 and Lyon point out that the retinal blood-vessels 

 are contracted to one-half or one-third their normal 

 calibre, and amaurosis may occur (it is possible, 

 however, that the retinal vessels, like the cerebral, 

 are not under the direct control of the vasomotor 

 system). Warmth does the patient more good than 

 cold, whereas if the cutaneous vessels were dilated 

 the reverse should be the case. Mr. Malcolm's 

 observations have not attracted the credence they 

 deserve, because it is so difficult to understand how 

 there can be a fall in blood-pressure with an efficient 

 heart and contracted vessels. 



Animal experimentation confirms the clinical 

 findings. Even Professor Crile consistently records 

 that the arteries in shock are empty. He also points 

 out that crushing the testes causes a primary fall 

 in blood-pressure without a previous rise ; the vaso- 

 motor centre, therefore, cannot be in a condition 

 of fatigue exhaustion. Seelig and Lyon measured 

 the outflow from the cut femoral vein of an animal 

 in five-second periods. The sciatic nerve was then 

 cut, and the flow of course increased in consequence 

 of the withdrawal of tonic vasoconstrictor impulses. 

 They repeated the experiment on animals in a 



