158 On the Efecf of Madder Roof 



future period. This process, which was before 

 but conjectural, or supported by analogy, phy- 

 siologists considered as fully proved by the 

 effects of madder upon the bones. They had 

 by this means an opportunity of seeing the 

 bones altered in colour, from the slightest tint 

 to the deepest red ; they could observe this 

 gradually removed, until the bones had re^ 

 gained their natural whiteness ;and explaining 

 the whole process on the principle of deposition 

 and absorption, they considered it as ocular 

 demonstration of a most rapid change in the 

 constituent elements of a part, of which, from 

 Us solidity, they could scarely have believed it 

 susceptible. 



I apprehend, however, that it is by 

 giving an erroneous explanation of the 

 phenomena ; by supposing that a change in 

 the osseous particles is denoted by an alteration 

 in their colour, that physiologists have con- 

 sidered this fact as conclusive. However in- 

 dubitable and well supported may be the 

 opinion, which attributes an imperceptible 

 change to the various parts of the body, we 

 shall, I believe, discover upon a more close 

 examination, that it is by no means supported 

 by the appearances, which the bones display 

 on the exhibition of madder root. The rapid 

 change in their particles, which such ap- 



