48 PLAIN FACTS FOR OLD AND YOUNG 



the arteries to the various parts of the body. Thence 

 it is gathered up by the veins, and carried to the npper 

 chamber on the right side of the heart. From this it 

 passes to the lower chamber of the same side, whence 

 it is forced through a large artery to the two lungs, 

 through which it passes for purification. It is then 

 carried by veins to the upper chamber of the left side 

 of the heart, whence it passes to the lower chamber of 

 the same side, from which it is again distributed to the 

 various parts of the body. The blood thus makes two 

 circuits before it gets back to its starting point, one 

 from the lower left chamber of the heart to the upper 

 right chamber, another from the lower right chamber 

 to the upper left chamber. 



A portion of the blood goes through two sets of 

 veins before getting back to the heart. The blood from 

 the stomach, spleen, and other abdominal organs is 

 gathered up in a large vein, which distributes it 

 through the liver by means of a second set of veins and 

 capillaries. After passing through the liver, which 

 produces some remarkable changes in it, another vein 

 carries it to the large vein which gathers blood from 

 the whole lower part of the body, and empties it into 

 the right side of the heart. This is called the portal 

 circulation. 



How to Take Care of the Heart.— A vigorous 

 heart is essential to a healthy and a long life. A man 

 with a weak heart is as poorly fitted for- the voyage of 

 life as a ship would be to cross the Atlantic with a 

 small or inefficient engine. 



Every organ in the body depends upon the heart for 

 its supply of blood, without which it cannot do its work 

 Without a sufficient supply of blood, the bones deterio- 

 rate, the muscles become weak, and every organ suffers. 



