148 On the Effect of Madtkr Boat 



other vegetable dyes, such as Logwood^ Tur- 

 meric and Alkanet Koot, did not communi- 

 cate therr respective tints t;o the bones,* 



This effect of madder upo.n the bones, was 

 soon afterwards made use of by Du I lamefj in 

 ills attempt' to prove the manner in which the 

 bones of aniroals are encreased in thickness. — 

 Observing in the vegetable kingdom, that the 

 bark, by a sort of secretion, formed the ligneous 



^ part of a tree, in, successive layers ; so he con- 

 ceived that the periosteum, or membrane sur- 

 rounding bones, being converted hito osseous 

 matter, encreased their diameter by adding to 

 them concentric laminae in succession. In 

 prder to prove the justness of his opinion, he 



jpiixed the food of a cock with madder root 

 for a month, withheld it for a month, and then 



From same experiments I made on young pigeon*?, f 

 found iba! a considerable quanlity of logwood, in the 

 form of extracJ, conimupicated an evidently purpl<^ 

 tint to the bones. Wi^h i:«?gJU',d,,t,o turrperic, it appears 

 to be aHered in its colour by passing throu^^h the digestive 

 organs, for the fceces of. ihe aniniid-, who took it in con- 

 siderable quantity, v^'ere constantly green : whilst either 

 logwood or madder root exhibited their rebpeclive hues 

 after passing t through the inlcbtines. Saifron exhibits pro- 

 perties different fronr) any of these substances; for 

 though a pij^con took it in considerable qnaniitv and 

 thereby had its fceces tinged, yet no perceptible altera- 

 liou of coltuir was produced in its bones. 



