130 On the Eject of Madder Root 



new formation of red and vvhlte osseous layers* 

 corresponding to the times (months) the 

 madder had been given or withheld. For, as 

 Mr. John Bell' very justly rem.arks, * " If a 

 "jbbne should increase by layers thick enough 

 " to be visible and -of a distinct tint, and such 

 *' layers be continually accumulated, upon 

 " each other every week, what kind of bone 

 " should this grow to?'* The only way in 

 which we can reconcile with each other the 

 phenomena observed in the difierent experi- 

 ments, and account for their apparent contra- 

 diction, is; by. supposing, that Du Hamel 

 mistook for an obscurely laminated appearance, 

 the variety in the tint, which is more deeply 

 communicated to the more solidy and more 

 faintly to the less compact parts of a.bone. 



This property of madder of tinging the 

 bones of animals, has lately been employed by 

 Dr. M'Donaldjf in his ingenious researches 



into the formation and death ; of bones. 



Amongst other objects, he attempted to as- 

 certain, in what manner and how soon, a 

 cylindrical bone is regenerated to supply the 

 place of one artificially killed. As the process 

 is highly curious, I shall briefly relate the prin- 

 cipal points. 



* Anatomy of the h(ne', &r. p J 5. 



•f Disputatio inaiiguralis fie Netro?) ac Callo. 1799. 



