238 MAN --AN ADAPTIVE MECHANISM 



by pain in these parts and not infrequently by head- 

 ache. In this early stage nitroglycerin often gives 

 temporary relief. Increased psychic strain causes a 

 corresponding aggravation of the symptoms. As the 

 disease progresses, there is continued numbness; the 

 pulsations of the supplying artery become weaker ; nu- 

 trition fails and slow atrophy of the parts follows. 

 The entire limb behaves as if the blood supply were 

 being gradually and at first intermittently shut off by 

 a clamp a clamp opened now and again, but finally 

 closed altogether. 



In the early stages of certain cases the patient may 

 improve or even recover if he takes a long pleasant 

 vacation or is buoyed up by new hopes and helpful 

 developments in his business. But if the environment 

 is not changed, there is the same inevitable progress to 

 destruction as under the same conditions is induced in 

 Graves' disease, cardiovascular disease or diabetes. 

 The same influences that modify these diseases, in 

 like manner and to the same extent modify thrombo- 

 angiitis obliterans. A return to the original activating 

 environment or a recall of the original harmful stimulus 

 may precipitate a return of the vicious circle. 



The tendency to relapse produced by nod association 

 (harmful recall) is illustrated by a woman who to a 

 marked degree exhibited the symptoms of this disease. 

 A trip abroad was prescribed and taken ; and during 

 three months of pleasant travel, the patient experienced 

 no symptoms. On her return she thought she was well, 

 until one day, while motoring in the city, she saw a 

 man killed by a street car. She directed her chauffeur 

 to drive on, but not before she had caught a glimpse 



