^$6 Experiments and Olfervations 



the phofphat of lime than is commonly found in the bones 

 of quadrupeds, &c. 



The different bones alfo of the fame fifh were various in 

 this refpeft j and the bones about the head of the fkate only 

 differed from cartilage by containing a moderate proportion 

 of phofphat of lime. 



It is at prefent believed, that phofphat, with fome fulphat 

 of lime, conflitutes the whole of the offifvins fubftance : and 

 perhaps the formation of booe from cartilage depends only 

 on the phofphat of lime ; but whether this is the cafe or not, 

 it is fit that I fhould notice a third fubftance, which con- 

 llantly occurred in the courfe of my experiments. 



When human bones or teeth, as well as thofe of qua- 

 drupeds and fifh, whether recent or calcined, were expofcd 

 to the aftion of acids, an effervefcence, although at times 

 but feeble, was produced. This circumftance at firft I did 

 not particularly notice j but the following experiments ex- 

 cited my attention : 



After the phofphat of lime had been precipitated from the 

 lolutions of various teeth and bones by pure ammonia, I 

 obferved that a fecond precipitate, much fmaller in quantity, 

 was obtained by the addition of carbonat of ammonia. This 

 fecond precipitate diflblved in acids with much effervefcence, 

 during which carbonic acid was difengaged, and felenite was 

 formed by adding fulphuric acid. Moreover the folution of 

 this precipitate did not contain any phofphoric acid ; nor did 

 the liquor, from which the precipitate had been Separated, 

 afford any trace of it. 



This precipitate was therefore carbonat of lime ; but I fiill 

 was not certain that it exifted as fuch in the teeth and bones. 



Although regular and comparative analyfes of the bones of 

 differer^t animals have not hitherto been made, yet by the 

 experiments of MefTrs. Gahn, Scheele, Macquer, Fourcroy, 

 Berniard, and the Marquis de Bullion, it has been proved 

 that phofphat of lime is the principal ofhfying fubftance of 

 tones in general, and that this is accompanied by a fmall 

 proportion of faline fubftances, and by fulphat of lime. 



I was therefore defirous to afcertain whether the carbonat 

 of lime, i\-hich I had obtained by the above-mentioned ex= 



perimeptSj 



