A LIVING EDDY. 245 



only the waste matters, leaving the valuable nourishing mate- 

 rial. But in disease the kidneys may throw out some of the 

 most valuable portions of the nutriment. 



Suppose that in. a mill, a workman, whose business is to 

 shovel out wastes, becomes crazy, and shovels wheat or. flour 

 out of the mill into the stream below. The diseased kidney 

 may be said to have become crazy, and in the disease called 

 "diabetes" throws out sugar, and in " albuminuria " excretes 

 albumen. So with the other organs, each seems to know what 

 to take and what not to take. It is as though the water sup- 

 ply of a city house was from the sewer ; each organ needing 

 a supply of building material acts like a filter, taking what it 

 needs, paying no attention to the impurities present, and the 

 organs of waste select the impurities, allowing the useful sub- 

 stances to pass on to the places where they are needed. 



A Living Eddy. Huxley has very aptly compared the 

 body to an eddy, whose form remains the same, but whose 

 particles are ever changing. 



" To put the matter in the most general shape, the body of 

 the organism is a sort of focus to which certain material parti- 

 cles converge, in which they move for a time, and from which 

 they are expelled in new combinations. 



" The parallel between a whirlpool in a stream and a living 

 being, which has often been drawn, is as just as it is striking. 

 The whirlpool is permanent, but the particles of water which 

 constitute it are incessantly changing. Those which enter it 

 on the one side are whirled around and temporarily constitute 

 a part of its individuality ; as they leave it on the other side, 

 their places are made good by newcomers. 



" Those who have seen the wonderful whirlpool, three miles 

 below the Falls of Niagara, will not have forgotten the heaped- 

 up wave which tumbles and tosses, a very embodiment of rest- 

 less energy, where the swift stream hurrying from the falls is 

 compelled to make a sudden turn toward Lake Ontario. 



