Q&Z CURIOUS OR USEFUL PLANTS. 



whose bones became red by eating madder mixed with their food * y 

 since that time various experiments relating to this subject have 

 been made, from which it appears that the colouring matter of 

 madder affects the bones in a very short time ; and that the most 

 solid, or hardest, part of the bones first receives the red colour, 

 which gradually extends, eb externo, through the whole osseous 

 substance, while the animal continues to take the madder ; and if 

 this root be alternately intermitted and employed for a sufficient 

 length of time, and at proper intervals, the bones are found to be 

 coloured in a correspondent number of concentric circles. Ac- 

 cording to Lewis, u the roots of madder have a bitterish somewhat 

 austere taste, and a slight smell not of the agreeable kind. They 

 impart to water a dark red tincture ; to rectified spirit, and to dis- 

 tilled oils, a bright red ; both the watery and spirituous tinctures 

 taste strongly of the madder + ." 



[Hort. Kewens* Millar. Lewis. 



SECTION VII. 



Copal J. 



Elaeocarpus copalliferus. Linn. 



The elaeocarpus genus comprises five species, of which all are 

 frees, chiefly indigenous to India or Australasia : the copal-tree, 

 copalliferous, constitutes one of these, and which is also found in 

 Africa and America. 



The resinous substance, called gum copal, and which is supposed 

 to be a secretion from this tree, is imported from Guinea, where it 

 is found in the sand on the shore. It is of a yellow colour, faintly 

 glistening, imperfectly transparent, and apt to break with a con- 

 choidal fracture. It is tasteless, and, when cold, inodorous. It is 

 used dissolved in rectified spirits of wine, or other volatile solvents, 

 both as a varnish, and as an astringent medicine. In North Ame- 

 rica, the natives obtain a very considerable quantity of this resin 



* Phil. Trans, vol. xxxix. p. 287. & p. 209. See also vol. xli. Afterwards 

 experiments were prosecuted by Bazanus, Geoffrey, Du Hamel, Fougeroux, 

 Bergius, and others. 



+ Mat. Med. p. 546, 



I For gum lac and cochineal, see the next book. 



