August 29, 1913] 



SCIENCE 



291 



of the sun strike directly upon the retina, 

 light pain causes an immediate protective 

 action; so too in the evacuation of the in- 

 testine and the urinary bladder as normal 

 acts, and in overcoming obstruction of 

 these tracts, discomfort or pain compel the 

 required muscular actions. This view of 

 pain as a stimulation to motor action ex- 

 plains why only certain types of infection 

 are associated with pain; namely, those 

 types in which the infection may be spread 

 by muscular action or those in which the 

 fixation of parts by continued muscular 

 rigidity is an advantage. As a further re- 

 markable proof of the marvelous adapta- 

 tion of the body mechanism to meet vary- 

 ing environmental conditions, we find that 

 just as nociceptors have been implanted in 

 those parts of the body only which have 

 been subject to nocuous contacts, so a type 

 of infection which causes muscular action 

 in one part of the body may cause none 

 when it attacks another. 



This postulate gives us the key to the 

 pain-muscular phenomena of peritonitis, 

 pleurisy, cystitis, cholecystitis, etc., as well 

 as to the pain-muscular phenomena in 

 obstructions of the hoUow viscera. If pain 

 is a part of a muscular response and occurs 

 only as a result of contact ceptor stimula- 

 tion by physical injury, infection, anemia, 

 or obstruction, we may well inquire which 

 part of the nerve mechanism is the site of 

 the phenomenon of pain. Is it the nerve 

 ending, the nerve trunk, or the brain? 

 That is, is pain associated with the physical 

 contact with the nerve ending, or with the 

 physical act of transmission along the nerve 

 trunk, or with the change of brain cell sub- 

 stance by means of which the motor-pro- 

 ducing energy is released 1 



We postulate that the pain is associated 

 with the discharge of energy from the 

 brain cells. If this is true, then if every 

 nociceptor in the body were equally stimu- 



lated in such a manner that all the stimuli 

 should reach the brain cells simultaneously, 

 then the cells would find themselves in 

 equilibrium and no motor act would be 

 performed. But if all the pain nerve 

 ceptors but one were equally stimulated, 

 and this one more strongly stimulated 

 than the rest, then this one would gain pos- 

 session of the final common path — would 

 cause a muscular action and the sensation 

 of pain. 



It is well known that when a greater 

 pain or stimulus is thrown into competition 

 with a lesser one, the lesser is submerged. 

 Of this fact the schoolboy makes use when 

 he initiates the novice into the mystery of 

 the painless pulling of hair. The simulta- 

 neous but severe application of the boot to 

 the blindfolded victim takes complete but 

 exclusive possession of the final common 

 path and the hair is painlessly plucked 

 as a result of the triumph of the boot 

 stimulus over the puU on the hair in the 

 struggle for the final common path. 



Persons who have survived a sudden, 

 complete exposure to superheated steam, 

 or whose bodies have been enwrapped in 

 flame, testify that they have felt no pain. 

 As this absence of pain may be due to the 

 fact that the emotion of fear gained the 

 final common path, to the exclusion of all 

 other stimuli, we are trying by experimen- 

 tation to discover the effects of simultane- 

 ous painful stimulation of all parts of the 

 body. The data already in hand, and the 

 experiments now in progress, in which 

 anesthetized animals are subjected to 

 powerful stimuli applied to certain parts 

 of the body only, or simultaneously to all 

 parts of the body, lead us to believe that in 

 the former case the brain cells become 

 stimulated or hyperchromatic, while in the 

 latter case no brain cell changes occur. 

 We believe that our experiments will prove 

 that an equal and simultaneous stimula- 



