1843.] 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



345 



THE PHILOSOPHY OF CORAL FORMATIONS, AND THEIR 

 ARCHITECTS. 



Coral (Corallium, Lat. from Kopn, a daughter, ami a\os, the sea; so derived 

 by Minshew, because it is generated from lite sea;) generally described as 

 an animal growing in a plant-like form, or a congeries of animals of the 

 polype khid : there are 15 genera at present known to us, embracing nume- 

 rous species. The ancients are wholly silent on the subject of coral reefs 

 and their architects, their knowledge, according to Dioscorides and Pliny, 

 being confined to the white and red corals of commerce, of which they enu- 

 merate six varieties or various shades, from dull white to bright red or scar- 

 let, the latter being held in the highest degree of estimation by the Romans, 

 who classed them among the most valued gems. But although silent, it 

 cannot be supposed that they were altogether ignorant of their existence, the 

 Red Sea, sometimes termed by the Hebrews the Sea of Zupli, or Weeds, hav- 

 ing been navigated from the earliest ages by the various tribes bordering on 

 the coasts, the dwellers of ancient Mesopotamia carrying on a constant trade 

 of drugs, spices, &c, with Egypt, Syria anil Palestine, and eventually with 

 European nations. We are therefore to assume that the perilous reef and its 

 beautiful architects were well known to them, as they are to the Arab an 1 

 Abyssinian traders of the present day, under the general term of stony 

 plants or weeds. C'nesalpinus, Boccone, Ray, Tournefort, Geoffroy, and Hill, 

 class coral among marine plants, maintaining that it is propagated by seed 

 like unto vegetables, and Count Marsigli, who was a very attentive observer, 

 supposed he had discovered its (lowers and fructification ; but the more mi- 

 nute observation of M. de Peyssonnel led to the discovery that what Count 

 Marsigli mistook for flowers, was no other than a congeries of minute insects 

 inhabiting the coral : for upon taking the branches out of the water, they 

 immediately retired into the cellular cavities, re-appearing on immersion in 

 water. Recent observations by Linna5tis, Ellis, and others, confirm these 

 latter views to a certain extent only, for in the face of these authorities, and 

 of many indisputable facts, it is still a subject of dispute as regards fungi, 

 sponges, and other species, and throughout the whole, the link of life between 

 the animal and vegetable kingdoms is so finely drawn as to be indivisible, 

 the beginning and the end being lost in the subtilty of nature's workings. 



The coral polyps, which are invisibly minute in their atomic structure, 

 perform a most astounding part in the production of earths, and of fossil and 

 mineral compounds. Governed in their distribution by habit and generic 

 character, they generate in groups and families in localities favourable to 

 the propagation and increase of their kind ; or they are disseminated by the 

 tidal currents, or by organic or inorganic substances to which they attach 

 themselves, throughout the various regions of the element in which they 

 live- In the colder latitudes, or in the lower depths, they are known as 

 naked polyps, being of the lowest order of organization and simplicity of 

 structure, gelatin and albumen together, or gelatin alone, with sea water, 

 being the chief, and in many instances their sole elementary compounds : 

 ' ut, as they approach the surface of the waters in temperate or tropical 

 regions, their organic structure becomes more rigid, and to the above simple 

 material is added, calcium, magnesium, sodium, iron, ammonia, marine acids, 

 and other well known products, by which, in warm and tranquil seas, they 

 become the unconscious architects of hills and chains of hills, mountains and 

 chains of mountains, rising above the w : aters as islands anil portions of 

 continents. 



The coral polyps are living but not sentient bodies, being m;re imputations 

 of life ; they are rapidly generated in warm and tranquil waters, and as the 

 grasses of the field, as rapidly disappear before the influences of climate, of 

 disturbance, and of the countless creatures of the deep that prey upon them. 

 Preserved from those contingencies common to all forms of life, such is the 

 peculiar economy of their structure and organic action, as to admit of a very 

 brief period of individual existence, the tender offshoot, like that of the 

 flowering shrub, being soon hidden in the more consolidated structure of the 

 compound body; every simple body, however minute on its parts, having 

 limits to its extent, such limits being defined by ami depending in its nature, 

 quantities, and qualities, and the influences by which it is generated and 

 governed : every compound body having also limits to its extent, such 

 ■pending, in like manner, on its nature, quantities, qualities and local 



influences, the same being perfect results of the day, still perfecting by ac- 

 quisition of parts and quantities, and passing througli the brief but successive 

 stages of development, from birth to maturity and from thence to decay. 



Many of these bodies propagate their kind by separation of parts, every 

 particle of the body having capacity, under favourable circumstances, to pro- 

 duce life : thus species are propagated and sustained : of such are the naked 

 polyps. Other species increase by the multiplication of their parts until they 

 have attained a certain size, defined by the accidents of clime and associ- 

 ation ; and becoming matured, their gemma or buds drop off, and carried 

 away by the waters, are generated therein, affixing themselves to some organic 

 or inorganic body where they increase and multiply their species; others 

 are permanently fixed to their primary bases, and increase by multiplication 

 of parts in a manner precisely similar to the growth of plants, ramifying 

 into shoots and branches, and becoming eventually one peculiar body of a 

 plant-like form, and having the appearance and qualities characterizing 

 species. The progressive development and growth of fung.sa or mushroom 

 species in the ocean and on the earth is precisely similar, although the one 

 is said to belong to the animal, the other to the vegetable kingdom ; both the 

 one and the other spring from corruption or decomposed organic matter — 

 both are developed by a gradual enlargement of the entire body, stem an I 

 crown produced by multiplication of parts — both attain a defined size and 

 form distinguishing species and characteristic qualities— both multiply by 

 their seed given forth through their cellular cavities — and both are incapable 

 of propagating by slips and cuttings. The same beautiful coincidence may 

 be remarked in many of the madrepores and millepores, their organica], me- 

 chanical, and chemical action similating with terrestrial plants, each having 

 root and stem, branches and leaves, each having its ascending and descend- 

 ing sap, and a governing action embracing the whole system ; the stems of the 

 corallines are composed of capillary tubes whose extremities pass through the 

 calcareous crust, and open into pores on the surface, and such is the d spo- 

 sition of plants. Many of the corallines consist of a single tube, as for in- 

 stance, Tubelaria, or pipe coral ; here the tube rises in the form of the cup of a 

 flower, such as the primrose: at first it is merely a flesh-like film contracting 

 towards the base when taken from the water, and expanding when replaced 

 in it ; Ihis film, consisting of gelatin, calcium, and sometimes a small portion 

 of animal oil, is the germ of the body, which strengthens with its growth, 

 and finally becoming rigid, its individual organic action is impeded, its pro- 

 geny appear and close the apex, and thus they continue to ramify into joints, 

 and when united in groups and families, the whole contribute to form one 

 vast catacomb, many of these jointed tubes rising up together, the living 

 crowning the whole, and still continuing to increase so long as they are unin- 

 terrupted by destroying causes. These polyps have the usual characteristic 

 of animal matter, but their mode of generation and development fully justify 

 Dr. Paris and others in insisting upon their belonging to the vegetable king- 

 dom. The same may be said of other species of the Polypiers Calciferes, which 

 in the place of a woody fibre have a calcareous substance mixed with their 

 animal juices, or forming their outward covering, the like organic action and 

 development being common to the vegetable kingdom. 



Polyps pass through the like gradations of change with shell fish ortender 

 succulent plants ; those of most calcareous nature not excepted. The stony 

 polyps develop two distinct stages of existence ; in the first they are naked 

 and flexible, and it is in this state that they are mistaken by naturalists, on 

 the one side, as tentacula of the animal, on the other as the flowers and fruc- 

 tification of the vegetable body. The fungous matter covering some, and the 

 flesh-like matter exuding from or covering others, is the rising progeny of 

 the consolidated mass beneath, convertible, and converted in the course of 

 time into like consolidated matter ; the basis beneath the external covering 

 of fungous matter consists of consolidated matter in which vital action is 

 still manifest, and consolidated matter in which vital action is extinguished, 

 the la'ter being in many cases converted into solid limestone rock, or as is 

 manifest in the corals of commerce, the degree of organic action simila'es to 

 that of forest trees. The Madrepora Fungitis, as Rumphius observes, while 

 living is covered with a thick viscid matter like starch, the more elevated 

 folds or plates having borders like the denticulated edges of needle-work lace, 

 which are covered with innumerable oblong vesicles formed of the same 

 gelatinous substance. This, and the coarse visible rind, is the active porlion 

 of the compound body appertaining to its calcareous bases, an I drawin [ its 



47 



