SHOCK 289 



dog, for example they may all have reappeared. The cause of this 

 shock is no doubt the sudden interruption of the nervous pathways 

 which reflex action ordinarily takes in the higher animals (see page 803). 



5. Nervous Shock; "Shell Shock," Considerable attention has been 

 paid to the nervous shock that has frequently been observed in men who 

 have been subjected to the harrowing sights and the constant noise and 

 nerve strain incurred in modern warfare. The symptoms may appear 

 suddenly at the front or they may develop in men who have comported 

 themselves in an apparently normal manner until removed to the rear, 

 when they pass into a condition more or less simulating that of shock. 

 Severe conditions may also result to soldiers from injuries which in nor- 

 mal individuals would not in themselves be sufficient to produce sur- 

 gical shock. The characteristic symptoms in such cases are entirely 

 different from those of other forms of shock, and, as has been shown by 

 Elliot-Smith and T. H. Pear, 25 the condition must be treated from the 

 neurologic or psychopathic point of view. 



6. Surgical Shock. It is this variety that is usually referred to when 

 one speaks of shock. It may be produced either by severe mechanical 

 injury to a healthy person or by extensive manipulation and rough 

 handling on the operating table. It is common in trench warfare, be- 

 ing therefore an important variety of " shell shock," which term must 

 be used only in a general sense. However produced, the symptoms of 

 surgical shock are very much the same. The patient lies in a quiet, 

 apathetic condition, caring little for what is going on around him, and 

 answering questions only when repeatedly and importunately questioned. 

 His skin, lips and gums are very pale and more or less cyanotic ; the skin 

 feels cold and is moist with sweat; the reflexes are greatly diminished, 

 and it is usually only after applying a very painful stimulus that any 

 movement of defense is elicited or resentment is shown on the part of the 

 patient. The postural reflexes are also abolished, so that if a limb is 

 lifted it falls back limp and toneless. The pulse at the wrist is very 

 rapid, thin and almost imperceptible, and the arterial blood pressure is 

 abnormally low. The respirations are frequent and shallow. The rec- 

 tal temperature is 1 C. or more below normal. The pupils are dilated 

 and react slowly to light. When he can be induced to speak, the pa- 

 tient's voice is hoarse, and he complains of cold and numbness in the 

 extremities. The symptoms are not unlike those of cholera. 



Experimental Investigations of Shock 



For inducing shock experimentally, two general methods have been 

 employed: either rough manipulation of the abdominal viscera, or re- 



