on the. Bones of Animals, IGl 



is freed from the colouring matter by the 

 excretions, the serum then exerts its superior 

 attraction, and by degrees entirely abstracts it 

 from the phosphate of lime, and the bones 

 resume their natural whiteness. In short, the 

 bones are at one time dyed by the colouring 

 matter, at another time bleached by the 

 serum. 



Whilst I have attempted to explain the ptd- 

 bable manner in which the bones, alre^ady 

 formed in an animal, at one time receive, 

 and at another are deprived of the colouring 

 matter of madder, I by no means intend to 

 assert ; that the phosphate of lime does not 

 acquire a similar colour during its solution in tlie 

 serum, or at the time it is precipitated from it 

 to enter into the composition of the bones ; 

 the fact is indisputable. I have, however, 

 found from some experiments lately made 

 upon a hen during oviparation,that only a slight 

 tinge can be communicated to the shell, fornied 

 whilst a large quantity of colouring matter is 

 circulating with the blood. So slight indeed 

 is the blush, that it would not be seen by a 

 common observer, unless contrasted with a 

 natural ^o^g : which is probably the reason 

 why it has, I believe, been denied by physi- 

 ologists, that the shell of the egg is altered by 

 the exhibition of madder. If this may be con- 



