18 THE ACTION OF THE LIVING CELL 



exhibit a highly characteristic series of symptoms: 

 generally diminished reflexes, and complete loss of 

 the postural reflexes, together with dilated pupils. 

 These are accompanied by extensive circulatory dis- 

 turbances manifested by a lowered blood pressure, 

 rapid but weak pulse, frequent and shallow respira- 

 tions, and a subnormal temperature. 



Taken collectively, these symptoms are termed the 

 shock syndrome, and the animal exhibiting them is 

 said to be in a state of shock. Since in such cases as that 

 just considered the state of shock results from an in- 

 jury, it is termed traumatic shock, to differentiate the 

 condition from shock induced by other means. 



Shock, or perhaps more properly the series of symp- 

 toms enumerated above, may be induced in various 

 other ways. For instance, if a rabbit, particularly one 

 with a large abdomen, is held by its head in an upright 

 position for half an hour, it will exhibit the symptoms 

 of shock, presumably because of the stagnation of 

 blood in the abdomen, and an inadequate filling of the 

 heart during diastole. If the rabbit is held in a binder 

 during the course of such an experiment, shock does 

 not ensue, because engorgement of abdominal vessels 

 is prevented. 



Any other condition which leads to the same circu- 

 latory difficulties, as for example extensive hemor- 

 rhage, produces a similar state of shock. The same 

 symptoms may be elicited by the injection of histamine 

 and various bacterial toxins, and an analogous state 

 has been frequently observed in certain pathological 

 conditions, such as intestinal obstruction. In such in- 

 stances, the condition has been designated as toxic 

 shock, 



