OF THE NATURE OF SPONGES. 67 



science.* The zoophytes here alluded to constitute a family 

 of which the Alcyonium orLobularia is the type ; and while 

 I think that the resemblance between it and the sponges has 

 been exaggerated, I must admit that there is an agreement, 

 sufficiently remarkable, in their composition. The fact is 

 that from chemistry the zoologist still borrows the best sup- 

 port to his claim upon the sponges. The peculiar odour 

 exhaled by them on being burned satisfied Hooke, the ce- 

 lebrated author of the " Micrographia,"t Ellis and Mon- 

 tagu ; and being familiarly known only as the effluvium of 

 animal incinerations, it continues to convince most of us 

 that, if not animals, the mass whence it proceeds must be of 

 an animal natm^e. " The analyses which have been made 

 of sponges," says ]\IjM. IMerat and De Lens, " by several 

 chemists, Geoffroy, Tromsdorff, Wclther, Hornemann, Fee, 

 &c. confirm their animal nature, as they fiu-nish, by distil- 

 lation, abundant ammoniacal products, wliich formerly 

 ■"known as volatile oil and volatile salt of sjwnge, v/ere put to 

 the same uses as the analogous products of other animal 

 matters. According to I\Ir Hatchett they consist essential- 

 ly of gelatine and of a membranous tissue presenting the 

 characters of coagulated albumen. Accordina; to Horne- 

 mann they contain osmazome, mucus and fixed oil. Dr 

 Fyfe of Edinburgh and subsequently i\I. Gualtier de Clau- 

 bry have ascertained the presence of iodine in the state of 

 an alkaline iodide, and M. Jouas more recently the existence 

 of bromine. Besides these they contain about half their 

 weight of carbonate and phosphate of lime, chloride of so- 

 dium, silica, alumina, magnesia and traces of sulphur. ":[: 



"• Fleming's Phil, of Zoology, ii. p. 612-13. 



t Micrographia, p. 137, 



\ Diet. Univ. de Maticre Medicale, v. vi. p. 512. 



