THE BIOLOGY OF DAILY LIFE. 15 



CHAPTEE III. 



THE LAW OF INTERCHANGE IN RELATION TO THE BODY IN 

 DISEASE, AND TO THE REMEDIES FOR DISEASE. 



UNLESS we fancied we could, at once, improve the 

 very ground-plan of Nature, we should, I presume, 

 never dream of putting into our body, with the intention 

 that they should remain in it, any substances (such as 

 mercury, arsenic, and most mineral and vegetable 

 drugs) which are not normal constituents of a healthy 

 human body, or resolvable into such constituents. 



To do this would be like mending a stone wall 

 with bricks ; it might possibly be an improvement, but 

 certainly would not be a restoration, and the aim of 

 all healing is professedly RESTORATION. 



No thinking man would take any mineral or vege- 

 table drug, unless it were under the belief that, after 

 the medicine had done some temporary work in the 

 system, it passed out of it altogether. If this were 

 not so the body would manifestly be permanently 

 altered, and so deranged, by the intended healing. 



In this view the proper practice of medicine may 

 be regarded as a kind of surgery, operating by almost 

 invisible instruments. Like surgery, it is & forcible 

 interference with the body, for the purpose of setting right 

 some injury, or remedying some wrong state of things. 

 But the surgeon never leaves his instruments perma- 

 nently located in his patient ! He even seldom leaves 

 any foreign material as a permanent part of the 



