POLYPUS. 



493 



On land the vegetable tribes absorb the carbonic 

 acid our inhalements have created, and return us the 

 life-giving oxygen. In the bosom of the deep the 

 Polypi absorb the calcareous salts brought from the 

 various countries whose coasts it has visited, which 

 salts, by a continued accumulation, might otherwise 

 prove as destructive to its inhabitants as the carbonic 

 acid proves to those on land ; but the Polypi collect, 

 decompose, and render them insoluble to the sur- 

 rounding element which their labours have thus puri- 

 fied ; they unite them into a mass of such extent that 

 in the progress of time the domain of man becomes 

 enlarged, and vegetation blooms and blesses with its 

 fruits on the structures that have ceased to serve 

 them. 



Let those, who thoughtlessly ask of what use are 

 these creatures, learn the fact, could no other be ad- 

 duced, that to the assistance of lime we owe the ele- 

 gance and solidity of our buildings, particularly the 

 latter. The calcareous stone or carbonate of lime, 

 that Proteus of the mineral world, is wholly wanting 

 in the equatorial regions ; may we not therefore be 

 permitted to consider these madreporous Polypidoms 

 as destined by Infinite Wisdom to supply its absence? 

 At Djeddah in Arabia, and on many other parts of 

 the coasts of the Red Sea, the houses are constructed 

 entirely with blocks of beautiful madrepore. In the 

 Indian isles, as well as in those of the Indian ocean, 

 and in many other parts, the madrepores are used for 

 the manufacture of lime. At Martinique also they 

 dredge them for that purpose from the bottom of the 

 sea. 



What could we substitute for sponge in domestic 

 uses ? where find a substance equal to this polypean 

 production in the property of imbibing water without 

 any diminution of elasticity or alteration of its nature? 

 The sponges we have in use are found in the equi- 

 noctial seas of both worlds, and in the warmest parts 

 of the temperate zones ; they are a considerable ob- 

 ject of commerce, many of the Mediterranean isles 

 have no other product to export. 



In France, and throughout Europe, the Coral Una 

 officiiialis is used as a powerful anthelminthic ; it is 

 known under the name of Coralline of Corsica, and 

 brought from the different parts of the Mediterranean ; 

 it is very abundant on the western coasts of France, 

 as also on the shores of England. Sir Humphry 

 Davy has remarked that it has a fattening tendency, 

 as well.! as others of its family. 



The inhabitants of Iceland, celebrated for its frosts 

 and its volcanos, make use of a rluslra, in the form of 

 snuff, to excite sneezing, either on account of its 

 agreeable smell, resembling violet, or as a preserva- 

 tive against the scurvy, so dangerous in its ravages 

 in those regions. 



On that well-known Polypidom, the RED CORAL 

 (his nobilis}, true stony coral of authors, we must 

 make a few short, remarks. It is so well known as a 

 material from which numberless elegancies of life are 

 formed, that a particular description of it were need- 

 less. In all ages and in all countries mankind have 

 acknowledged its beauty. Warriors have employed 

 it in the ornamenting of their weapons ; men and 

 women in the decoration of their persons and houses ; 

 the physicians of the middle ages looked upon it as 

 a universal remedy ; and the priests of ancient re- 

 ligious sects esteemed it as an object acceptable to 

 the gods. 



Coral then may be a name retained to distinguish 



the above species par excellence from the other Poly- 

 pidoms of a stony texture. Its natural figure is tree- 

 like ; it is inarticulated, the axis stony, stiff, and suscep- 

 tible of the highest polish ; the rind is fleshy, becoming 

 chalky and very friable by desiccation, and always 

 adhering to the axis ; this is equal to marble in soli- 

 dity, which, being formed of concentric layers, they 

 become perceptible by calcination ; its surface is 

 more or less striated ; the striae parallel and unequal 

 in depth. 



A reticulated body, formed of small membranes, 

 with numberless vessels and glands filled with a milky 

 juice, appears to unite the rind with the centre. This 

 reticulated body is found in all corticiferous Polypi- 

 doms ; the rino is of a less deep colour,. of a soft sub- 

 stance, and formed of small membranes and slender 

 filaments ; it is pierced by tubes or vessels, and 

 covered with tubercles, which are thinly scattered 

 and have a large base, the summit of which is termi- 

 nated by an opening divided into eight parts. In 

 the interior is found a cavity which contains a white 

 and almost transparent potypus, its mouth surrounded 

 by eight conical tentacula slightly compressed, and 

 ciliated on their borders. 



This coral is found in different parts of the Medi- 

 terranean and Red Seas, it grows in all directions, 

 and each trunk forms a perpendicular to the level 

 from whence it springs ; it attaches itself to all rocks, 

 whatever may be their nature ; it is also found on 

 unfixed bodies, such as fragments of lava, stone vases, 

 broken glass, and specimens have been exhibited in 

 museums adhering to a variety of bodies. 



When coral is once detached and at the mercy of 

 the waves, it soon loses its polypiferous rind ; to 

 enable the constructors of this brilliant edifice to 

 labour for its increase, it is indispensable that it should 

 be fixed ; their work does not, however, advance with 

 a rapidity equal to that of the madreporic Polypi in 

 the Indian sea, or the immense Eastern Ocean, whose 

 labours, in the short space of a few years, close the 

 entrance of marine ports, and raise those gigantic 

 reefs we have already been describing, on which 

 many vessels, sailing in those distant regions, have 

 struck and perished. 



Coral is found at different depths in the bosom of 

 the waters, but, notwithstanding the density of the 

 medium in which it exists, all aspects are not suitable 

 to its increase. On the coasts of France it covers 

 those rocks that face the south ; it is rarely met with 

 on those having an eastern or western aspect, and 

 never in a northern one. It is never found at less 

 than three or four yards below the surface of the sea, 

 nor ever at a greater depth than 350 yards. 



In the straits of Messina coral prefers an eastern 

 aspect, on the south it is seldom found, and still less 

 on the rocks of the north or west. They there fish 

 it from a depth of 100 to 200 yards. In those straits, 

 immortalised by Homer and Virgil, the solar rays 

 strike more perpendicularly than on the coast of 

 France, their heat penetrates to a greater distance, 

 .and the coral is found even deeper than 300 yards ; 

 but then its quality no longer compensates for the 

 risks and numerous difficulties attending the procuring 

 of it. 



On the north coast of Africa it is not sought be- 

 yond thirty or forty yards in depth, and at a distance 

 of three or four leagues from shore ; they abandon it 

 when it reaches 250 or 300 yards. 



The coral is generally of'a more beautiful colour 



