408 



Late experi- 

 ments of Dr. 

 M'Dmald oft 

 the bones. 



Very cutious 

 procefs of a 

 bone deflroyed. 



—and the regu. 

 far proce/s of 



ON THE EFFECT OF MADDfiR KOOT 



periments I have made on the fubje6t, I have found 'the bones 

 ot young pigeons tinged of a uniform rofe-colour, internally 

 as well as externally, in twenty-four hours. This communi- 

 cation of colour to the whole fubftance of the ofleous fyftem 

 in fo (liort a time, makes it highly improbable that the laminated 

 appearance, remarked by Du Hamel, was produced by the 

 new formation of red and white ofleous layers, correfponding 

 (o the times (months) the madder had been given or withheld. 

 For, as Mr, John Bell very juftly remarks,* '* If a bone fliould 

 increafe by layers thick enough to be vifible and of a difiin^l 

 tint, and fuch layers be continually accumulated upon each 

 other every week, what kind of bone fliould this grow to?" 

 The only way in which we can reconcile with each other the 

 phenomena obferved in the different experiments, and account 

 for their apparent conlradiflion, is, by fuppofing that Du 

 Hamel miftook for an obfcurely laminated appearance, the va- 

 riety in the tint, which is more deeply communicated to the 

 more folid, and more faintly to the lefs compact parts of a 

 bone. 



This property of madder of tinging the bones of animals, 

 has lately been employed by Dr. M'Donald,f in his ingenious 

 refearches into the formation and death of bones. Amongft 

 other objeds, he attempted to afcertain in what manner and 

 how foon a cylindrical bone is regenerated to fiipply the place 

 of one artificially killed. As the procefs is highly curious, I 

 (hall briefly relate the principal points. 



Dr. McDonald's experiments were made by amputating the 

 proper leg-bone of young pigeons or chickens immediately 

 above the joint. The marrow was then extraded, and the 

 cavity which contained it, filled with lint. This procefs cau fed 

 the death of the bone, and the formation of a new -bone fur- 

 rounding that deflroyed enfued. Immediately after the expe- 

 riment, the animal had its food mixed with madder root, and 

 the part was infpefted in different animals, at different pe- 

 riods. 



On examination three days afterwards, the periofleum cr 

 enveloping membrane, was found much thickened ; and un- 

 derneath it a gelatinous humour was ef^'ufed, furrounding the 



* Anatomy of the bones, &c. p. 15. 



t Difputatio inaugural is de Necrofi ac Callo. 1T9^. 



dead 



