66 THE OCEAN. 



been perceived in them when living, even though 

 violence in many modes has been offered to them ; 

 though beaten, pinched with hot irons, cut or torn, 

 or subjected to the action of the strongest acids. 

 The substance may be destroyed, but there is no 

 contraction, nor the slightest evidence of feeling; 

 to all appearance they are as passive as the rock on 

 which they grow. One proof of their animality, 

 however, is open to any one : we are all familiar 

 with a peculiar smell produced when horn, wool, 

 feathers, &c, are burned ; this smell arises from the 

 presence of ammonia, and is peculiar to animal mat- 

 ter ; on burning a bit of Sponge this animal odour 

 is strongly perceptible. On viewing a living Sponge, 

 however, in water, with care and attention, it is 

 found to exhibit a constant and energetic action, 

 which sufficiently shows its vitality. Dr. Grant's 

 account of his discovery of this motion in a native 

 species is so interesting, that, though I have quoted 

 it in another treatise, I may be forgiven for repeat- 

 ing it here. "I put a small branch of the Sjwngia 

 coalita, with some sea-water, into a watch-glass, 

 under the microscope : and on reflecting the light 

 of a candle through the fluid, I soon perceived that 

 there was some intestine motion in the opaque par- 

 ticles floating through the water. On moving the 

 watch-glass, so as to bring one of the apertures on 

 the side of the Sponge fully into view, I beheld, for 

 the first time, the splendid spectacle of this living 

 fountain vomiting fortli from a circulnr cavity an 

 impetuous torrent of liquid matter, and hurling 

 along in rapid succession, opaque masses, which it 



