'i'Q'2. PHILOSOPHICAL TRANSACTIONS. [aNNO 1751. 



The substance of coral, by a chemical analysis, scarcely furnishes either oil, 

 salt, or phlegm : live coral with its bark furnishes about a 40th part of its weight 

 in these ; but the bark of coral alone, in which are contained these animals, 

 affords a 6th part. These principles resemble those drawn from human scull, 

 hartshorn, and other parts of animals. 



After the accounts here laid down, we are able to assign the reasons of all the 

 particular facts we observe in coral. We see why a branch of it, broken off and 

 detached from its stem, may flourish. It is because the coral insects, [worms.^ 

 which are contained in its cells, not having been injured, continue their operations : 

 and drawing no nourishment from the stem of the coral, are able to increase, de- 

 tach and separate. How they live and are nourished, is proposed to be explained 

 in treating of the urtica of the madrepora, in which these animals are vastly 

 larger, and appear very distinctly. 



In each hole or star of the madrepora, on which our author lays the evident 

 proof of his new system, the urtica, placed in the centre of each pore, causes it 

 to increase in every direction by lifting itself farther and farther from the centre 

 of the stone. And in coral, and in the lithophyton, the urtica, being niched in 

 their crusts or barks, deposits a juice or liquor, which runs along the furrows 

 perceived on the proper substance or body of coral, and, stopping by little and 

 little, becomes fixed and hard, and is changed into stone ; and this liquor, being 

 stopped by the bark, causes the coral to increase proportionably, and in every di- 

 rection. In forming coral, and other marine productions of this class, the 

 animals labour like those of the testaceous kind, each according to his species, 

 and their productions vary according to their several forms, magnitudes, and 

 colours. 



After what has been here laid down, none will surely consider these marine 

 productions as mere plants ; they are truly zoophytes, formed by the labour of 

 the animals, which inhabit them, and to which they are the stay and support. 



Swammerdam seems to have proceeded very far in these discoveries, as we may 

 see by his 1 Qth letter to Boccone. He goes further, and says, that having with 

 a microscope examined a piece of coral, he found that each particle of it was 

 composed of 10 or 12 angular and crystalline spherules ; and having sawed across 

 a piece of coral, and given it the highest polish, he found, with the microscope, 

 and even without it, that coral from its centre is disposed in strata, which he 

 conjectures are formed by the application of the above-mentioned spherules. 



M. de Reaumur having been made acquainted with whatM. de Peyssonnel had 

 observed, sent him a letter in the year 1726; where he takes notice, that no one 

 had hitherto considered coral as the work of insects. But it seemed to him dif- 

 ficult to establish this doctrine in the generality of marine productions, as was our 

 author s opinion. That in whatever mode you considered coral and lithophytes. 



