■on ///'• Hears' of Animal^'. 155 



^' Uon with various mordents, as tl^.cir basis. — 

 " the colouring of the bones of a living animal 

 " by means of madder, is, in every circum- 

 " stance, analogous to the formation of these 

 " lakes. The colouring matter of madder, 

 ** passing unaltered through the digestive 

 " organs of tlie animal, enters the general mass 

 ^* of fluids, and is dissolved in the serum of 

 **' the blood, to which, indeed, if it be in 

 " large proportion, it communicates a sensibly 

 *' red tinge- Bui there is akvays present in the 

 " bloody and in a statue of solution hi the senon, 

 " a quantity u^' the earthy matter of tJie bones^ 

 ^' phospiiute of lime, ready to be deposited, as 

 '' the exigeneies of tlw animal may require, — 

 ** Now the phosphate of lime is xin excellent 

 " mordent to madder and has a strong affinity 

 " to ity and is consequent b) admirably fitted to 

 ** afford a base for the colouring matter of it ; 

 " in suck experiments y therefore, they concrete 

 '^ in the state of a bright red lake, wheme the 

 " colour of the hones is derii^ed. That this is 

 ''* actually the case, may be shewn by a variety 

 '** of experiments. Thus, if to an infusion of 

 " madder in distilled water, be added a httle 

 " of the muriate of lime, no change is per- 

 ** i:eived : but if to this mixture be added a 

 " solution of the phosphate of soda, imme- 

 '* ^diately a double elective attraction takes 



LT '2 



