NICOTINE AND ADOLESCENCE 137 



artery throbs with the beating of the heart, the needle of the 

 sphygmograph traces its way across the smoked paper and 

 leaves its scientifically exact record there in black and white. 



The boys were interested in the way the machine worked, 

 and in what it told about their heart action before and after 

 smoking. 



The records were taken at different times during the year, 

 and each was slightly different from all the others, just as 

 the handwriting of one person always differs from that of 

 another. On the whole, however, the various reports of the 



SPHYGMOGRAPH RECORD OF THE HEARTBEAT OF A YOUNG vyoMAN ON 



THE VERGE OF NERVOUS PROSTRATION 

 The young woman does not smoke. (From Dr. McKeever) 



sphygmograph explained two apparently contradictory facts, 

 both of which are perfectly well known : 



1 . The smoker says he feels better, is able to think faster 

 and to work harder, just after smoking than before the 

 smoking began. 



2. Athletic coaches say tobacco prevents success. They 

 therefore prohibit its use by their men. 



It is as if one honest man said, " Smoking does me good," 

 while another man, equally honest, says positively, " Smoking 

 does you harm." 



To reconcile these differences, we turn to the diagrams 

 borrowed from Dr. McKeever's record. Notice that one of 

 these shows the heartbeat of a tired young woma/i. She did 

 not smoke, but she was on the verge of nervous prostration. 

 Compare this with the heartbeat record of the vigorous young 



