on the Bones of Animals. 153 



this conclusion ; that the osseous system of the 

 animal will be renewed three times during the 

 period, which the formation of the substitute 

 bone requires ; a conclusion which we should 

 be inclined to reject merely from its improba- 

 bility. But besides this, the appearance of 

 the parts strongly militate against it — for, if 

 we may judge at all of the activity of the 

 process in the two parts, by their comparative 

 degrees of vascularity, that employed in form- 

 ing the substitute bone far exceeds that going 

 on in the osseous system generally ; one strik- 

 ing phenomenon attending the regeneration of 

 a bone being, the very high degree of in- 

 creased vascularity, which the parts employed 

 in the process rapidly assume. 



After this effect of madder upon the bones 

 was known, it long remained a mystery, why 

 some other white parts of the body, such as 

 nerves, cartilages and periosteum, were not 

 equally liable to be coloured by it, as the bones. 

 This fact, I believe, did not receive any ex- 

 planation, until Dr. Rutherford gave a very 

 ingenious and satisfactory one. When spcak- 



for the osseous system, according to ihe experiments of 

 the 'most respcciable physiologibts, acquires a deep red 

 tint from madder in one week, and assumes its nalural 

 colour in another. 



