191 1.] IN RELATION TO THE EMOTIONS. 83 



fire waiting in vain for orders to charge suffers more than the 

 soldier that flings himself into the fray; that a wild animal in an 

 open chase against capture suffers less than when cowering in cap- 

 tivity. An unexpressed shmibering emotion is measurably relieved 

 by action. It is probable that the various energizing substances 

 needful in physical combat such as the secretion of the thyroid, 

 the adrenals, etc., but which are not consumed in action may, if fre- 

 quently repeated, cause physical injury to the body. That the brain 

 is definitely influenced, even damaged by fear has been proved by 

 the following experiments : 



Rabbits were frightened by a dog but not injured, and not chased. 

 After various periods of time the animals were killed and their 

 brain cells compared with the normal. Widespread changes were 

 seen. The principal clinical phenomena expressed by the rabbit 

 were rapid heart, accelerated respiration, prostration, tremors, and 

 a rise in temperature. 



The dog showed similar phenomena — excepting instead of mus- 

 cular relaxation as in the rabbit the dog showed aggressive mus- 

 cular action. Both the dog and the rabbit were exhausted and 

 although the dog exerted himself actively and the rabbit remained 

 physically passive, the rabbit was much more exhausted. 



Further observations were made upon the brain of a fox chased 

 for two hours by members of a hunt club, then finally overtaken 

 by the hounds and killed. The brain cells of this fox as compared 

 with those of a normal fox showed extensive physical changes in 

 most of the cells. 



The next line of evidence is oft'ered with some reservation but 

 it has seemed to me to be more than mere idle speculation. It 

 relates to the phenomena of one of the most interesting diseases in 

 the entire category of human ailments — I refer to exophthalmic 

 goiter or Graves' Disease — a disease primarily involving the emo- 

 tions. This disease is frequently the direct sequence of severe 

 mental shocks or a long and intensely worrying strain. The follow- 

 ing case is typical. A broker w'as in his usual health up to the panic 

 of 1907. During this panic his fortune and that of others was for 

 almost a year in jeopardy, failure finally occurring. During this 



