360 Mr. Hatchett's Experiments on Zoophytes, 



after the solution of the phosphate of lime, was of a gelatinous 

 consistency, and exhibited but very imperfect traces of organi- 

 zation ; by the others, however, a completely formed membrane 

 or cartilage was left, retaining the figure of the original bone. 



When therefore the component parts of shell and bone are 

 considered, it appears that the essential characteristics are, car- 

 bonate of lime for the one, and phosphate of lime for the other; 

 and that their bases consist of the modifications of a glutinous, 

 gelatinous, or membranaceous substance. 



I experienced much gratification in tracing the progressive 

 and connected changes in the composition of the various shells 

 and bones ; and a considerable increase of pleasure arose, in pro- 

 portion as the observations made on those bodies were corrobo- 

 rated, and the chain of connection extended, by the develope- 

 ment of the facts resulting from the experiments on Zoophytes, 

 which form the principal subject of this paper. 



It will now be proper to review these experiments, and to 

 examine how far they agree with those made on shell and bone, 

 and how far they tend to prove, that these substances are all of 

 a nature closely connected. 



The experiments on the Madrepores afforded the following 

 results. 



Madrepora virginea, when examined by acids, left but very 

 little of any gelatinous substance or membrane. 



Madrepora muricata, and Madrepora labyrinthica, afforded 

 loose portions of a transparent gelatinous substance. 



Madrepora ramea, and Madrepora fascicularis, when deprived 

 of the carbonate of lime by acids, remained in the state of com- 

 pletely organized membranaceous bodies, which exhibited the 

 original figure of the respective Madrepores ; and the proportion 



