326 DETAILED SYNTHESIS. 



life, varying also according to health, exercise taken, 

 state of mind, etc. 



932. THE CAPACITY OF EACH VENTRICLE is at least 

 between one and two ounces, and if 80 beats per minute 

 are made, and only one ounce is received and thrown 

 out, it will equal five pounds per minute, three hundred 

 pounds, or more than a barrel, per hour ! 



933. Inf. The contemplation of the statistics of the labor per- 

 formed by the heart, and of the great change that must go on in the 

 body to render such action necessary, must convince every one of the 

 importance of properly exercising and rubbing the body, and indeed of 

 doing everything that will exert a favorable influence on the circulation. 



934. Remark. IF EXERCISE QUICKENS THE HEART'S ACTION ten 

 beats per minute, that circulates ten ounces more blood per minute, or 

 forty pounds more per hour ; an immense advantage hi the way of pro- 

 moting changes hi the body. 



935. THE HEARTS ARE CONSTRUCTED of three tissues: 

 Sinewy, Muscular, and Secretory. 



936. THE NECESSITY FOR TWO HEARTS arises from 

 the fact that all the Blood of the body, as soon as it has 

 passed through the capillaries, needs to be acted upon 

 by the air, and must be therefore forced through the 

 lungs as soon as it can be drawn together from the cap- 

 illaries. The delicate structure of the capillaries of the 

 lungs would not tolerate the force necessary to drive 

 the Blood through them and then out into all parts of 

 the body, or, if they would, such a force would drive the 

 Blood through them too rapidly; therefore, after the 

 Blood has been passed through the lungs, it must be re- 

 ceived by another heart. 



937. Inf. Since the Blood loses more than it gains in the lungs, 



THE SECOND HEART MENTIONED NEED NOT BE SO CAPACIOUS AS THE OTHER ; 



but as it must drive the Blood farther, and through greater obstructions, 

 it should be thicker and stronger. 



938. Inf. Since the same Blood that goes through the lungs is to 

 be thrown out, BOTH HEARTS SHOULD BEAT THE SAME NUMBER OF TIMES 



982. What-? 938. What do statistics of heart show? 934. What if ? 935. Of 

 what tissues - ? 936. What ? 937. Why need - ? 938. Should ? 



