PHYLOGENETIC ASSOCIATION IN RELATION TO THE 



EMOTIONS. 



By GEORGE W. CRILE, M.D. 



(Plates I-VIII.) 

 {Read April 22, 19 11.) 



To the surgeon every variety of the human emotions in the var- 

 ious stations of Hfe, from infancy to senihty, in health and in disease 

 is presented. Not only does the surgeon come in intimate contact 

 with emotions displayed by the victims of disease and accidents but 

 he also observes those manifested by the remainder of the family 

 circle and friends. Then, too, he is unhappily forced to notice the 

 effects upon himself when he is waging an unequal battle against 

 death — the strain and worry at a crisis when a life is in the balance 

 and a single false move may be fatal is an experience unknown to 

 others as it is to the operating surgeon. 



My personal experience as a surgeon and an experimental re- 

 search of my associates, Dr. H. G. Sloan, Dr. J. S. Austin, and Dr. 

 M. L. ]\Ienten. and myself furnish data for this paper. 



On this occasion I shall limit my discussion mainly to the strong- 

 est emotion, viz., fear. I believe that it can be shown that the 

 emotion of fear can be elicited only in animals that utilize a motor 

 mechanism in defense against danger or in escape from it. For 

 example: the defense of the skunk is a diabolic odor which repels its 

 enemies. The skunk has no adecjuate equipment, for defence or 

 escape by muscular exertion. The skunk has little or no fear. 

 Again certain species of snakes are protected b}^ venom. They 

 possess no other means of defense nor adequate motor mechanism 

 for escape. They show no fear. Other animals because of their 

 prowess have but few fears. The lion, the grizzly bear, and the 

 elephant are examples. Animals having armored protection, as the 

 turtle, have little fear. It is therefore obvious that fear is not uni- 

 versal. The emotion of fear is felt only in those animals whose 



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