134 THE HUMAN BODY 



Training. If any person attempt some unusual exercise he 

 soon finds that he loses breath, gets perhaps a "stitch in the side," 

 and feels his heart beating with unwonted violence. If he perse- 

 vere he will probably faint or vomit, as is frequently seen in the 

 case of imperfectly trained men at the end of a hard boat-race. 

 These phenomena are avoided by careful gradual preparation 

 known as " training." The immediate cause of them lies in dis- 

 turbances of the circulatory and respiratory organs, on which 

 excessive work is thrown. 



