THE CIRCULATION 1 15 



beat may be rapid and palpitating. This condition is 

 known to physicians as the " tobacco heart." The short 

 period of palpitation has caused it to be named in Eng- 

 land, the " trotting heart." Physicians who have made a 

 special study of the subject, claim that one out of every 

 four tobacco users has the tobacco heart. It prevents 

 success in athletic contests and feats of strength. It pre- 

 vented a large proportion of the young men who applied 

 for enlistment, during the recent war with Spain, from 

 entering the army. Knowing the paramount importance 

 to sound health of rich blood and perfect circulation, 

 we are ftot surprised to know that the whole body is 

 enfeebled by tobacco, and that mental as well as physical 

 vigor is impaired. Observant teachers can often tell 

 which of the boys in school are addicted to the use of 

 tobacco from the comparative inferiority of their ap- 

 pearance and from their indolence of body and mind. 



203. THOUGHT LESSON. Comparison of Arteries and 

 Veins. (If this is made a written exercise, underline the 

 words which you supply.) 



Walls. The walls of the are very elastic, while 



the walls of the are slightly elastic. The walls of 



the are thicker and stiffer than the walls of the . 



It is necessary that they should be so, because they must 

 sustain the of the . 



Work of each. The arteries take pure blood from 



the to the , and impure blood from the 



to the . The veins take pure blood from the 



to the , and impure blood from the to the . 



Connections at heart. The are connected with the 



auricles. The are connected with the ventricles. 



Rate of flow. The blood flows more rapidly in 

 the . 



Manner of flow. The blood in the flows uniformly. 



The blood in the flows . 



