SURGICAL SHOCK 275 



rine secretion (c/. Chapter VII) and this liberated epineph- 

 rine may play a part in protecting the normal animal against 

 histamine poisoning. 



Swingle and Parkins 611 have also studied the effect of various 

 types of trauma on the arterial blood pressure of dogs with and 

 without adrenal glands. Unlike the experiments of previous 

 authors these were performed on animals adrenalectomized 

 some days previously and kept alive by injections of cortical 

 extracts. Swingle and Parkins found their adrenalectomized 

 animals, supposedly maintained in good health on an adequate 

 supply of the cortical hormone, to be extremely susceptible to 

 traumatic shock. Administration of cortical hormone restored 

 the adrenalectomized animals from a state of shock. The 

 authors concluded from their experiments that depletion of 

 the adrenal cortical hormone is the causative factor in surgical 

 shock. 



Swingle and Parkins' conclusion is not proven, however, by 

 their experiments. It is well known that animals after adrenal- 

 ectomy go into profound shock under the effects of minor 

 stimuli, an observation which has been noted by numerous 

 workers. It is obviously necessary to conclude therefore that 

 adrenalectomy (or more specifically the loss of adrenal cortical 

 function) leads eventually to a state of shock which resembles 

 in many ways that observed from a variety of other causes. 

 To conclude, however, that shock in general is due to inade- 

 quacy of the adrenal cortex, as Swingle and his collaborators 

 claim, is not valid. The hypersusceptibility of their adrenalec- 

 tomized animals to trauma is evidence only of inadequate 

 therapy with the cortical hormone as the results of their own 

 experiments, in which injection of hormone prevented shock, 

 indicates. Restoration of adrenalectomized animals from 

 shock by treatment with the hormone also proves only the 

 long known fact that adrenalectomy reduces the tolerance of 

 animals to influences which precipitate an animal into a state 

 of shock. As has already been stated in Chapter IX, there is 



