and Observations on the component Parts of Membrane. 343 



by the addition of ammoniac ; after which, lixivium of potash 

 formed a less copious precipitate of carbonate of lime. 



Some parts of the cortex were separated, by beating the Gor- 

 gonia between folded writing paper, and were immersed in the 

 acid. 



This solution was scarcely rendered turbid by ammoniac ; but 

 afforded a considerable portion of carbonate of lime by potash. 



The stem from which the above cortical part had been sepa- 

 rated, was next examined by the dilute acid, in which, when 

 steeped during three days, it became soft, elastic, and in some 

 measure cartilaginous. 



The acid was saturated with pure ammoniac, and then 

 changed to a deep yellow or orange colour : a large quantity of 

 phosphate of lime was at the same time separated ; and but very 

 little carbonate of lime was afterwards precipitated by potash. 



The recent stem in great measure retained its shape, when put 

 into a red-hot crucible ; but that which had been steeped in the 

 acid, curled up, and soon became a shapeless mass of coal, 

 which, by a longer continuation of the red heat, was completely 

 dissipated. 



This difference appears to have been caused by the phosphate 

 of lime, which was present in the recent stem, but was dissolved 

 and separated in the latter case by the acid.* 



These experiments prove, that the Gorgonia Flabellum, like 

 the Gorgonia ceratopbyta, consists of a horny stem, containing 

 a certain portion of phosphate of lime ; and that this stem is 

 invested with a membrane, hardened principally by carbonate of 



* These different effects are to be observed, when bone, and when the cartilage or 

 membrane which remains after bone has been long steeped in acids, are subjected 

 to a red heat. 



MDCCC Y y 



