LEDGER ACCOUNT OF BODY. 241 



process of evolution, has brought man to the erect posture, 

 aiid enabled him to walk on one pair of limbs. Now, for him 

 to try suddenly to reverse this long process of development 

 and walk on his hands, with his whole body up in the air, is 

 doing violence to his structure, and is likely, if followed to 

 any considerable extent, to be attended by injury. Not that 

 the gymnastic apparatus is bad ; but that; in the main, exer- 

 cises that conform more nearly to the natural condition of 

 man's upright position are more natural, and, as a rule, bet- 

 ter. So all the games that call for running, jumping, etc., are 

 naturally preferable to climbing, etc. 



Ledger Account of the Body and its Organs. 

 Through the digestive tube and lungs the body receives addi- 

 tions ; and there is a corresponding loss through the lungs, 

 skin, kidneys, and intestines. So a ledger account might be 

 kept with the body ; and it should balance in the long run, 

 since in adult life the weight remains practically constant. 



So we might take a single organ, say the liver, and balance 

 its accounts. It receives a large amount of blood. To offset 

 what it takes from the blood, it gives to the intestines a large 

 quantity of bile, and to the blood it gives glycogen. 



It is especially interesting to note the losses and gains of 

 the blood as it passes through the various organs of the body. 

 A river, flowing past one State after another, will take some 

 of the soil of each, and deposit some of its muddy particles 

 on the banks of each State. Of course, the blood is unlike 

 the river, in that it empties into itself; i.e., it is truly a 

 circulation. The blood takes something from, and gives some- 

 thing to, each organ as it flows through it. From the intes- 

 tine the blood gets the chief part of its new material in the 

 newly digested food. To the muscles the blood gives nutri- 

 tive material and oxygen, and receives water, carbon dioxid, 

 and other waste matters. The account would be a good deal 



