172 MAN --AN ADAPTIVE MECHANISM 



hausted by fighting ; of electric fish before and after 

 electric discharge; of salmon before and after their 

 exhausting run up the Columbia River to their spawn- 

 ing beds. (Figs. 30, 31, 32.) We examined the organs 



A. 



Cerebellum of salmon from ocean. Cerebellum of salmon from head- 

 waters of Columbia River. 



FIG. 30. EFFECT OF A LONG SWIM ON BRAIN-CELLS OF A SALMON. 



Exhaustion is shown by the disappearance of chromatic material from 

 the Purkinje cells in B. 



(From photomicrographs, X 310.) 



of animals exhausted by excessive emotional excitation ; 

 of animals exhausted by strychnin convulsions; of 

 animals to which had been given alcohol, nicotin, 

 morphia, scopolomin, ether and nitrous oxid ; of animals 



