322 MAN --AN ADAPTIVE MECHANISM 



out a fixative fluid or exudation. As a secondary adap- 

 tation, the stomach contents are ejected by vomiting, 

 so that a protective anorexia against useless food 

 also stands guard. 



If our conclusions are correct, why are certain cases, 

 familiar to every surgeon, of widespread general peri- 

 tonitis, cholecystitis or of other abdominal lesions 

 unaccompanied by pain, often without muscular 

 rigidity or tenderness even, so that the surgeon may 

 be misled in his diagnosis, and the result may be fatal ? 

 In seeking an explanation for these cases, which are 

 almost invariably found either among the aged or the 

 very young, we are led to formulate a postulate re- 

 garding the source or the site of pain. 



The Site of Pain 



If pain is a part of a muscular response and occurs 

 only as a result of stimulation to muscular activity by 

 physical injury, infection, anemia or obstruction, in 

 what part of the nervous arc may the mechanism for 

 the production of pain be found ? Are the pain phe- 

 nomena associated with the physical contact of the 

 stimulus with the nerve ending ; with the process by 

 which the impulse is transmitted along the nerve 

 trunk ; or with the process by which the energy in the 

 brain-cells is released and the impulse to the muscles 

 is transmitted ? It seems most probable that pain is 

 associated with the discharge of energy by which the 

 motor act is made possible. 



If this be true, then, if every contact ceptor in the 

 body were equally stimulated in such a manner that 

 all stimuli reached the brain-cells simultaneously, 



