214 THE HOUSE I LIVE IN. 



worn off by friction in our motions, but it also 

 takes away the worn out and good for noth- 

 ing particles, and carries them out of the body. 

 It is true they are taken up by the absorbents 

 in the first place ; but then the absorbents 

 carry them to the blood, and empty them into 

 it, which amounts to the same thing. In this 

 way, as you may easily see, the blood is liable 

 to lose its purity and excellence, since it is 

 constantly giving out good particles, and re- 

 ceiving bad ones.* 



MOTION OF THE HEART. The heart is 

 kept in motion, we know not how; nor can 

 the wisest anatomist or physiologist in the 

 world tell us. We know that the lungs have 



* The manner in which the bad or waste particles 

 are removed from the system is very curious. The 

 kidneys seem to be a sort of sieve or filter; with this 

 difference, however, that while a sieve permits only 

 the finest and l)est parts to pass through it, the kid- 

 neys filter out the worse or coarser parts. These 

 are carried in two pipes called ureters, to the blad- 

 der, whence they are conveyed immediately out of 

 the system. 



