1 64 ELEMENTARY BIOLOGY 



incomplete oxidation, and it is likely that much of the irrita- 

 tion as well as of the stimulation is due to these rather than 

 to the nicotine.^ 



196. Effect on the heart. The evidence on hand may be taken 

 to show that the habitual smoking of tobacco can lead to an 

 irregularity of heart action. This may not be dangerous in 

 itself, but probably makes the heart less reliable in an emer- 

 gency. This is one of the reasons why athletic coaches do not 

 permit those who are in training to use tobacco in any form 

 and in any amount ; when it comes to a critical test, the non- 

 smoker is more likely to come up to the requirements of the 

 athletic field. 



197. Effect on the nerves. The smoker feels a soothing 

 effect from his smoking, but after a while this effect wears off 

 and he needs another smoke to soothe him again. As time 

 goes on, the interval between smokes is shortened or the 

 strength of the tobacco, or the size of the cigar, is increased. 

 We may compare this to what happens in the case of the 

 alcohol user. 



Aside from the effect upon the feelings, the nicotine in 

 many cases produces a certain iinsteadiness in the action of the 

 nerves. This may show itself in dimmed vision or eyestrain, in 

 lessened precision of hand work, in weakened attention to the 

 day's work, or in an increased tendency to absent-mindedness 

 or day dreaming. 



198. Effect on growth. The most marked effects of smok- 

 ing are produced on grozving boys. 



In a large high school in Illinois an investigation was made 

 for the purpose of finding out whether smoking made any 



1 A special objection to cigarette smoking is said to be the fact that the 

 slow burning of the paper results in the formation of a substance, called acro- 

 lein by the chemists, which is highly poisonous. The effects of this are sup- 

 posed to be cumulative ; that is, " piling up." The carbon monoxid formed 

 by the slow oxidation of tobacco and paper is also a source of injury, as this 

 gas, when inhaled, is absorbed by the red corpuscles. 



