380 GENERAL ANATOMY. 



lion of the bones, are especially proved by the effects of mad- 

 der upon them. 



Mizauld first,* and Belchiert a long time after, were the first 

 who observed that when madder (Rubia tinctorum,} is given 

 to animals mixed with their food, their bones become red. 

 Duhamel, Boehmer,| Detlef, J. Hunter, || and several others 

 have made curious experiments on the same subject. Ruther- 

 fordll has explained the effect of madder on the bones alone, 

 and to the exclusion of all the other parts of the body, by a 

 chemical affinity of the colouring matter of madder for the 

 earthy substance of the bones. 



Duhamel found, in his experiments, that the bones of young 

 animals are coloured much sooner than those of old animals; 

 that the progress of their tincture and ossification is so much 

 the more rapid the more vigorously their growth goes on; 

 that when the madder is discontinued, the bones become 

 white again, and that the return to their original colour is 

 effected by the superposition of white layers upon the red. 

 This last fact is also fully demonstrated by Hunter's experi- 

 ments. Duhamel, however, imagined, notwithstanding these 

 decisive experiments, that the bones enlarge in thickness by 

 extension. 



As to the growth in length, Duhamel's experiments also led 

 him to think that this growth, which he compares to vegeta- 

 tion, takes place by the extension of their parts. It is proba- 



* Ant. Misaldus. Centitr. MemorabiKum seu arcanorum omnis generis, 

 1572. 



fPhilos. Trans, vol. xxxix. 1736. 



+ Radicis rubise tinctorum affedus in Corp. JLnim. Lips. 1751. Ejusdem 

 prolusio, qua callum ossium a rubias tinctorum radicis pastu infectorum descri- 

 bit. Ibid, 1752. 



Osrium calli generatlo et natura perfrada in animalibus rubise, radiee 

 pastis, ossa demonstrate!. Goet. 1753. 



U Exper. and observ. on the growth of bones, from the papers of the late 

 Mr. Hunter, by Ev. Home, in Trans, of a Society for Improvement, &c, 

 vol. ii. Lond. 1800. 



\Bisput. Med. Inaug t de Dentium Formaiionc d StrudurA, &c. Auct.R, 

 Blake. Edinb. 1798. 



